1. the booting speed
2. visual aspect
3. it keeps all your needed drivers (sound, display ..)
4. programs install faster then before (like WoW - I don't play but my friend tried)
5. It comes with Windows Defender (better than not having any av at all)
6. after trying it you won't want to install xp again :P
And you can disable things that annoy you like
http://www.epstudiossoftware.com/blo...UAC-Prompt.png