I have a standard test where I hold the phone securely and with one hand, then with 1 thumb reach across to the furthest corners. If I have to stretch and can't touch (e.g. Galaxy S3) the corners then it's too big, and not for me. The iPhone 5 has quite literally the perfect sized screen for me.
If I wanted a big screen, I'd get a tablet and I did I got an iPad and I love it and because I have the phone as well I didn't bother getting a cellular iPad, I just make a wireless hotspot and badaboom internet.
If I wanted a big screen, I'd get a tablet and I did I got an iPad and I love it and because I have the phone as well I didn't bother getting a cellular iPad, I just make a wireless hotspot and badaboom internet.