This is not exactly a question of belief... Head to PhoneArena.com, search HTC Hero, and you'll see all the specs.
You'll still be able to use EDGE, which will let you download at 8-12 kilobytes per second (tested with T-Mobile's access point epc.tmobile.com). To get an idea, you'll be able to have Google Maps follow you while driving at freeway speed, but only in map mode. In Satellite mode, the data will download too slow. EDGE doesn't work while a call is in progress.
You can move apps to the SD card using Astro.
It feels a bit smaller than the iPhone, and looks sleek. Got compliments from women on it.
(Please spell "I'm" correctly). 3.2" is a good side, but you'll need a day or two to adjust from 3.5". After that, it will feel natural. I did GPS driving fine on that size, and web browsing as well.
It depends. If you want 3G connectivity (T-Mobile only, though), or camera flash, or FM radio, get the Nexus One. It will be 2-3 times the price, though. If you want a solid phone, running Android 2, buy a used HTC Hero (I'm selling).