I have been using Samsung Galaxy S2 for more than a year now and I am planning to sell it because of very poor battery backup.
I need to charge the phone thrice a day now it is very disgusting and also the one gb ram capacity is not enough seen enough for the smooth working. It sometimes get stuck for minutes while using multitasks and I need to restart the phone for getting it started again. I will prefer other phones like xiaomi or asus at this price!