What I was used to before I got the G1 was a Samsung Trace, which could not be considered any sort of "smart phone". No Qwerty keyboard, tiny screen, etc. I did not actually use the original iPhone until about a year ago when a friend gave me an unlocked 2G when she got a 3GS.

I don't know much about the subject of text input, but there are two distinctly different implementations between android and iPhone. Android tends to be more predictive, but less enthusiastic about what it thinks you mean, and hence less corrective. I find the more decisive autocorrect on iPhone OS to work out much better for me. It's less about picking out words from a suggestion list and more about just banging away on the keyboard and trusting the software knows what I mean.