TBH, my 4.3" is a little too be big IMO. The iPhone has it right, if you can't operate it with one hand, it's too big. I dread the times when I have to scroll down the notification bar because I can't reach it with my thumb properly. 4.0" is the max IMO.
Oh for sure, I love the use of swiping to get around, very intuitive and lets be honest, swiping is a lot cooler than "tapping" anyway.