Well, I started off with an iPhone 3g.. used it for 5 months.. sold it and bought the Nexus one. Unfortunately, lost my N1 couple months ago... bought the HTC Desire... and a week ago my uncle gifted me the iPhone 4...
1. Reception of the iPhone 4 is insane(where i get 4-5 bars on desire, i get 1-2 on the damn iPhone)
2. I agree the screen of the iPhone is b-e-a-utiful, but I have to lower the brightness if i want more battery life.
3. I get around 22-23 hrs battery life on my desire.(with sync on, wifi on all the time, around 40-50 mins of calling). Whereas the iPhone fetches me around the same time, but without any calling, without browsing, just some music and games.
If I were given an option, HTC DESIRE all the way. Iphone is just too boring.