Having owned both an iPhone and the G1, I'd have to say that there are pros to both of them. Sure, the iPhone is prettier, but the one thing that the G1 has that the iPhone never will is an open source OS. This allows the phone to have limitless possibilities which pretty much rockets it far ahead in my opinion.
I beta tested the Pre, and while it's a very nice phone, it doesn't hold a candle to the G1 or the iPhone. Also, Sprint just plain sucks in my opinion
Now, as far as the MyTouch goes, it's pretty and has Android, but if you are planning on typing a lot of texts or emails, the on screen keyboard may get to be a pain.
Hope I helped and WELCOME!