As for using an iphone I am not sure as I have never used one but I am much happier with my Touch Pro than I think I would be with a iphone. It can do everything an iphone can (probably more) and it has a slide out keyboard and removable storage (up to 32 gb microsd cards). Also I wouldn't want to be stuck with att. Sprint had much better service and better prices where I live.
btw chronoguy did you buy a video cable for your pro or did you mod the audio adapter? I was thinking about modding one of my adapters and install it permanently in my vehicle (I got a defective Pro and sent it back for a new one and when I sent it back I got to keep all the accessories for it including the battery and battery cover).
If anyone has any suggestions for a touchscreen let me know.