I was in same situation in end decided just to get 3 original ones, and made sure i was getting none fake ones.
as I had bad experience with cheap Chinese battery that melted, these ones that promise Higher capacity in same size of original's are load of sheep sh*t they usually don't even last as long as the original capacity ones.
you can sometimes get lucky and get a bit better, for alot more than original battery price, but i don't think its worth it to be honest..
thanks - but the reviews, as they all do with these things - seem to be largely negative. I dont want to go down the route of an extended back as it wont fit my Otterbox. I'll just carry round a usb charge pack and a cable in my bag.
I've got a Chinese gold 2450Mah for my Samsung Galaxy Ace, I'm getting the SII next week and to be honest I'm going to get another one from them as this one lasts soooo much longer. On the Ace the original 1350 was about 9 hours, the 1500 I got was about 12 hours and the 2450 Hong Kong job does a good 15-18 hours.