1. Never needs rebooting as it never locks up, hesitates, etc. I've even loaded up 12 applications and switched back and forth, run 4 at a time with no hesitation at all. This is the first PDA device I have had that can do this. On my old XV6800, I could load up 4 applications and begin to switch back and forth but in 10 to 15 minutes, it would become sluggish and require a reboot to fix.
2. Touch Flo 3D- Makes the screen wiz by in scroll mode, Fastest screen redraws of any phone I have seen and only the iphone can equal it ( or vice versa ) The Droid is good but the TP2 has it beat in a side by side test. Where you really notice this is in scrolling down through contacts that are synced with my Outlook on the PC. It will wiz down through hundreds and when you get in the region where you want, say the m's, touch the screen and it stops where you can then scroll slower to find your contact. The speed of the scroll is the speed you swipe your finger across the screen.
3. The built in apps are really nice and I didn't need to buy or go to 3rd party, such as the stock portfolio, Google Maps, RSS application, weather, Opera browser, PDF reader, Yahoo finance, etc already loaded from htc.
4. Hardware-
Ability to plug in a small low cost accessory cable and pull stereo audio / Video and connect to a large screen TV. The application converts the screen to TV compatible video and it is pretty sharp. Makes internet surfing, movie watching, and gaming easier with a big screen. I've always wanted this capability. Prints e-mail and winword excel power point stuff etc to a color laser printer via wifi on your lan. It's an application they built in.
5. The application integration is much better. It is more like an iphone in how you can easily be on a phone call, and snap a picture and send it to the other person and not have to go through all sorts of application musical chairs to do that. With CDMA you have to have wifi to do simultaneous web browsing and any TCPIP connections while on a phone call. The phone call takes priority. However, you can still view your e-mail during a call that was received before the call was made. The AT&T add is a bit misleading on this I saw. I also have my phone set to record all conversations and save them to MP3 files on my uSD card. This is automatic on every call. I could never do that with my old XV6800. I do this with a 3rd party application, however. I don't know if it is possible with the built in Notes voice recorder. The app is Audio Notes.
6. OK that was 5 from me but I know digiblur would jump on my case if I didn't mention his favorite- the ability to custom the ROMS to make the phone unique. I really haven't found a need to compel me to experiment there yet. Too much to do with it stock and this PDA really works.