I bought three of the Anker batteries from Amazon in mid November of 2012, and I've been using those exclusively since then. When I bought them, they were $8.99 each. They work great and the phone displays the battery percentage remaining just like with the OEM battery (some generic batteries I've bought for a digital camera do not give an accurate readout of power remaining). I think the Anker lasts at least as long as the original Samsung battery. The Anker comes nicely packaged with instructions, suggesting a bit higher quality standard than most generic batteries I've purchased in the past for other devices. The instructions state that they should not be stored fully charged, something I was not aware of, so I charged the extras to around 90% before storing them. When I used one for the first time two months later, it was still at that charge level, which I guess is to be expected.