I'm about to upgrade from Windows 7 Ultimate to Windows 8 (Enterprise) and have to decide whether to do a clean install or an in-place upgrade. Traditionally, I've always regarded a clean install as the "only" alternative, and it seems that many still think that way. On the other hand, shouldn't the upgrade process have improved since back in the days of Windows 95? Some people claim that "garbage" left behind during the upgrade can be reclaimed using the disk cleanup tool, for example.
Does anyone have concrete examples of known issues with the in-place upgrade from Windows 7 to Windows 8?