Ive kept holding on for my SGSII.... its a great phone! and with custom firmware its faster than most new phones aswell!
The battery in my almost 3 years old phone was getting bad, so i bought this and now my phone is even better than it was from the start!
The back gets slightly bigger but not anything that matters.... the phone also gets heavier but in my opinion thats not really a bad thing! now it feels more robust.