Don't do a clean install if you are going from Windows Vista. I have performed many upgrades for many people, and while it does take longer, it keeps absolutely everything. As for the is it worth it, IMO, it is more than worth it. The difference is like going from Windows 98 to Windows XP, even though they look similar. The performance upgrades are well worth the money, too, as almost every aspect of performance has been upgraded (DirectX 11, etc) and it better than XP IMO.