I like them. The batteries are rechargeable and hold their charge very well. I use them in a Razer Viper V3 Hyperspeed mouse. Because the battery voltage drops very gradually during use, even when it is nearly completely drained, it can still operate without any strange response jitters, whereas alkaline and lithium batteries lose their voltage abruptly at around 5% and disconnect. The charger gets quite warm when charging the batteries, even though it is the slow-charging model. I feel confident charging them one at a time to extend their lifespan. I should mention that I prefer the way the battery terminals are held in place during charging rather than charging via USB like some others, because the USB port is more delicate, and if it gets dirty, it is harder to clean so that it makes good contact. I should note that I have only been using them for 3 months now, as of this review, and their health is still at 100%. If they were to be used in a very low-power device, such as a remote control or a wall clock that someone might keep for 10+ years without changing the batteries, Eneloops will last longer without recharging than lithium batteries, while alkaline batteries may have started leaking by then and damage not only the alkaline batteries themselves, but also the device they are used in. Users say their Eneloops have never leaked, and they have been on the market for over 20 years and are still working—something I have also confirmed with first-generation Eneloops that have been in my home for a long time. They are noticeably heavier than other AA battery chemistries, something those of you who care about the balance between weight and capacity and drain them much more frequently should take into account. For example, lithium batteries are ideal for drones because they can discharge faster, are lighter, and have greater capacity.