Having played with both, I'm kinda torn. Pure wow factor definitely goes to the WebOS based Pre. Hardware wise, I liked the keyboard on the G1 better. The new Android phone lacks a physical keyboard, so if that one is an option, definitely look into how people are getting along with the virtual keyboard. I have no idea how close it is to the one on the iPhone.

Both have great webkit based browsers, though the Pre has multitouch for zooming. The browser also seemed to rum smoother then it did on the G1.

I'd be pretty divided if I was trying to decide between the two.