You get used to the size pretty quickly, although using my old SGS2 (which seemed HUGE when I got it) is really strange now, as it seems tiny in comparison.
The thing I'm being constantly blown away by is the resolution. Moving up from 480x800 to 1920x1050, the difference is crazy.
The best thing is, with just a bit of research I managed to get it for only £25 a month, with unlimited data, and the handset was free. Ker-ching.