I am always dubious of buying batteries from manufactures I have no experience with. A lot of batteries are of low quality and don't work as well as originals even if they are supposed to be better. This is not the case with this Anker battery.

The look and feel of a battery isn't something that you usually worry about but this Anker battery is solid and the labels covering the cell are on firmly - basically it doesn't feel cheap or that corners were cut. I have noticed the battery is slightly bigger than the standard Samsung battery for the Galaxy S II but it still works perfectly with all accessories and the back cover of the phone still fits (albeit more snugly).

The performance of the battery was surprising for the price. An official Samsung battery for the phone costs three times as much as this battery but is outperformed. I noticed modest gains in battery life - 1 hour on standby, 30 minutes of music and about 20 minutes on a call but these are real world gains, not promises. One surprising thing I noticed was how cool the battery ran. If you have used the Galaxy S II heavily you will have noticed the heat of the battery and the area around the camera. This battery does not get as hot as the standard battery under heavy use which is a surprising welcome.

The Anker battery works superbly as a replacement for the original or as an extended battery. Basically this battery is cheap, last longer than the standard battery, runs cooler and is solidly built. I can't think of any reasons why you should not purchase this for the Galaxy S II.