I've had these for a couple months now and they are comparable to the stock Samsung battery. However, take note that they are not of the same quality. If left charging through the phone too long the battery has a good chance to die. I have one deceased battery but the other is still in good shape. Now I know not to overcharge these batteries because they are very delicate. On the flip side, they are very reasonably priced and have saved my butt on more than one occasion. I recommend a purchase