After 8 months of use, the only thing I can say is that if the Xiaomi 14T were a device in the Research and Development stage, it would be just fine. I would say it has potential. For a device that is sold normally and even at 400 euros, well... that's too much!

Let me explain:
Its biggest problem is video. Whatever setting you try, whether 1080p, 4K, 30 or 60fps, it constantly has frame drops and stutters that make watching the video simply tiring. If you try to shoot a landscape and move the phone a little, it looks like you're filming with a 50-euro drone that lost its GPS. If someone wants to shoot a decent video, they just skip it without a second thought.

The battery is another mystery. One day it lasts normally, the next you see the percentage dropping faster than a stock in crisis without having changed anything in the apps or your usage. The consumption in general is bad and VERY unpredictable.

(update 24-11-25)
The phone now behaves unpredictably and when taking photos it shows artifacts, distortions like shadows in the photos or it may photograph ghosts, depending on how you see it... I attach photos below.

The software is full of bugs. Although it has received so many updates, it still has issues, the most annoying being the Wi-Fi bug where you are normally connected, but suddenly the internet just... disappears. And you are left staring at the Wi-Fi icon winking at you ironically. I won't mention secondary bugs like not opening an app for 2-3 days and it does something like a wipe on the data by itself without me using any cleaning app or any setting in developer mode.

On the positive side:
Yes, it is a fast phone, yes it has a bright screen and loud sound, but all phones have these nowadays, even those costing 150€. For the 400 euros it asks, I expected something more stable and less “experimental.”

P.S.: The 14T pro series as well as the entire 15T/15T pro series also have the same bugs regarding video.

UPDATE: Now the disappointment has reached its peak, since after 5 months of careful use, the charging port has started to fail and the cable does not make good contact. This has only happened to me once before with a phone, and that was after 4.5 years of use.
I'm lowering the rating to 1/5 because there should be a limit to the quality of materials, aside from the lousy software.

A long analysis and strict but objective review follows. Fanboys - xiaomi enjoyers will surely hate, but for those who want an unbiased opinion, happy reading.

I won't separate the phone into positives and negatives, but into main categories. The review is after 1 month of use.

*Edit*: The rating from 3.5 goes straight to 2/5. The reason? Lately, the phone freezes and can't make or receive calls. When someone calls me, the phone doesn't get a line, gives a continuous tone, and doesn't ring. When I call, it might beep briefly and immediately hang up. Sometimes, after a while, I'm notified of missed calls, other times not even that. I haven't changed any settings, VoLTE is enabled, the option to switch to 2G network is allowed, but still nothing. Sometimes it just refuses to make/receive calls. (The SIM has been checked in another phone).

Overall, full disappointment... Hand on heart, stay away from xiaomi, especially if you're going to spend a significant amount.

1) Camera: The phone has a lens that gives you many possibilities IF you know what you're doing. If you know photography as a hobby or job, you can do wonders (as in the example in the 2nd astrophotography), but if you just point and shoot in auto, the results won't blow your mind. In auto, the phone can't choose the SS (shutter speed) correctly, so if there's a moving part in a photo, it comes out blurry (as in the 1st photo where the cat/subtitles on the TV are blurry), and in this case, the cat was walking slowly, not running. Also, the color processing, even though you have 2 options with vibrant/authentic mode, in cases of strong contrasts like the last 2 photos, it can't cope very well, but with a bit of after processing you can easily get it to your liking.
That's for the prime lens. The x2 lens is very good during the day, loses quality dramatically at night. The ultrawide is very average, which is expected for the category.
In short, it can take excellent photos if you shoot in pro or do processing. 4/5 for the price.

2) Speed: Here I'm very conflicted. The phone initially seems fast and hasn't frozen heavily. However, it doesn't feel as snappy compared to other possibly better phones. Personally, I'm coming from the legendary Nova 5t and have used many phones in all categories.
Examples that bother me a bit about speed:
If you go to the photo album and use the side arrow to go to old photos, it takes ~2 seconds to load them. This never happened on my old phone and, oddly, doesn't happen on my brother's redmi note 11, so I don't understand why it lags. And ok, it's a nitpick, but if it does this now as new, in 2-3 years with 70%+ storage, how will it behave? For reference, the nova 5t, a phone over 5 years old, with storage always full at 98%, still doesn't do this, everything is instant.
Because of this and the general feeling, 4/5.

3) Software: This is the phone's Achilles heel. It's the WORST software I've ever encountered. 90% of this phone's problems are purely due to its software.
Complex with 5000 things and small "smart" features, which are unnecessary, while other important ones like secure storage are missing.
The UI for me is ugly and hard to use. Most of the time when I'm looking for something special I end up searching with Chatgpt's help and barely figure it out (with samsung, iphone, Huawei I never had such issues).
Also, if you use social media a lot, good luck. Since I got the phone, often in messenger or Instagram, a voice message/recording/video or a story won't play. You tap it and the phone does nothing. If you close/open the app, it fixes. At first I thought it was a META bug that would get fixed. Time passed and the issue never got fixed. After checking with friends, it hasn't happened to anyone with iphone/Samsung recently, while a friend with Xiaomi also said "Yeah, it happens sometimes, just restart and it fixes."
Sorry, but for me this is unacceptable. I can't accept that a phone worth over €500 new has so many software bugs, and I'm just mentioning some big examples.
2/5 and that's being generous.

4) Battery: First days, pure disappointment. The phone wouldn't last a day, I had to charge it almost twice a day. Now things have improved a bit and if I start my day at 100% it usually lasts. With simple use I get about 6 hours SoT (browsing, social, 1 bt watch connected, gps off). But be careful! The phone behaves completely differently if it starts from 100% than from 75%. After it drops below 60%, the battery starts disappearing rapidly, whether you use the phone or not. The problem is probably due to software, the phone drains a lot on standby. You might not use it and it loses ~2-3% in an hour, while if you play games, compared to other phones, it manages much better and drains less. Overall, I'm not satisfied with the battery because it's very unreliable. I've gone to sleep with 46% and woke up with 30%. Other times I've gone to sleep with 80% and woke up with 76%. I feel it's totally random. In any case, expect on average 5-6 hours SoT. Charging with a compatible xiaomi charger is very fast, with a no brand/Huawei 22.5w charger, it's very slow. 3.5/5

5) Screen+Sound: I left the best for last. Excellent resolution screen, super crisp with very good colors, gets bright enough for use in the sun and low enough for use in the dark, overall it's very pleasant to watch videos on this phone. The sound is also a very strong point. Loud and quite high quality, it won't disappoint. 5/5

6) Calls/microphone/speaker: Mixed feelings about signal. I've been on a plateau where 2 other phones (also xiaomi) had no signal while I barely had some days, but I've also walked in Peristeri and suddenly lost signal under power poles and the person on the other end couldn't hear me, while in the same workplace compared to my previous phone there are still interferences and I have to go outside the warehouse. My callers haven't complained, though a colleague asked if I was wearing headphones because I sounded further away. The earpiece speaker is very loud with good sound. 4/5

Bonus detail: The fingerprint sensor works perfectly if you place your finger exactly, but if you put it a bit higher/lower/right/left it might not work at all.

Overall, a disappointing experience for me compared to my previous phone and the money I spent. If the phone had different software and bugs, silly lags, difficult interface disappeared and battery drainage improved, the phone would be 5/5 for the price. Right now, for €400, I'd only go for it if the main thing I cared about was the camera and screen for watching movies/whatever.

overall rating: 3.5/5

If someone is used to xiaomi software and is ok with it, then the phone automatically gains much more value. But if someone has another phone with serious software, they should think seriously about it

I have been using the phone for about 4 months. Overall, it is more than satisfactory for the price it currently costs. Its camera, both for photos and videos, is excellent, especially during the day. At night, it produces a satisfactory result which I consider superior compared to the competition in this particular price category. The processor is incredibly fast and will not disappoint, while the screen offers everything the average user needs. Finally, I want to mention the only problem I have identified, which might concern someone considering buying this device. That is its battery, which does not last a full day of normal to demanding use, resulting in needing to charge it twice a day (the second time can be as little as 20 minutes since its charger is very fast and will charge the phone from 30 to 70 in that time, but still, it requires you to charge it even for a little while). In conclusion, I would recommend it to anyone who is okay with not having great battery autonomy on their phone.

I have had the phone in my hands for 5 months. I am extremely satisfied! The photos, if you know a little, easily rival expensive iPhones. The videos are very clear and stable with various features like cinematic, director mode, stabilizer, HDR, and so on. I wouldn't say it's better than an expensive iPhone, but it's very close. I expected nothing less with LEICA and Sony sensors. The screen is perfect, very good resolution and clarity, especially with 144hz, it's addictive. The sound (which I don't think is that important) is still very good with stereo speakers, and for gaming and music, it's sufficient. PROCESSOR! .... lightning fast. For gaming, for work, for everything, especially if you increase the RAM from 12GB to 24GB. Finally, the battery. Yes, okay, as they say, it could be a little better, but with these specifications, it's okay. I charge it to 80% and try not to let it drop below 25%. With heavy use, it will need a second charge during the day, but with 20 minutes to charge it to 80%, it doesn't bother me. Fully charged to 100% and with heavy use, it barely lasts the day. One of the best phones on the market right now and one of the most affordable!

Well, let me write my review for a phone that has undoubtedly shaken things up in its category, and rightly so. My previous device was the Huawei P30 Aurora Blue, which I was absolutely satisfied with for 5.5 years. Now I have the Xiaomi 14T Titan Black, the base version with 12/256. I will focus on the main points worth commenting on after two weeks of use. Let me start with the only "weak" point of the device, which is the battery. It's certainly not bad as many have written; I just believe that Xiaomi could have done a little better here in terms of management or perhaps have a 5,200 capacity, like the Honor 200 Pro. This doesn't particularly bother me as my usage is normal, and the phone easily lasts 24 hours. Of course, I should mention at this point that with charging in 45 minutes and the 67w charger, you forget all about it. In all other aspects, I am very satisfied, as the processor is really fast, clocked at 3.35 GHz (first time with Mediatek; I have used Exynos, Kirin), the display is amazing with a 144hz refresh rate, even higher than the 15ultra, and think about 4,000 nits maximum brightness that makes night into day. The cameras are stunning, tested in the most difficult conditions, in night shots. All the sensors are high quality both front and back. Kudos to Leica, Sony! I don't want to comment on the materials used as they don't particularly concern me since it's in a case every day... However, it has a very beautiful design and will go down in history with those kitchen eyes on its cameras :D It could definitely have a Gorilla Glass 7i instead of 5, but I believe a protective glass can save it. It has IP68, very useful because the phone needs to be protected from water and dust to some extent. The connectivity is excellent on all levels; I also have the Redmi Buds Play 6 with me. In conclusion, VFM, and as a first-time Xiaomi owner, I declare myself a fan!