The only thing that does annoy me is not having a 'My Computer' and 'Control Panel' in the start menu. I've changed that now by pinning them there though but the search wasn't originally working so was a pain in the arse to get to the control panel every time.
If you right click on the start menu you'll get control panel, file explorer and other handy shortcuts. Right click on start menu more useful than left click =P
I had some issues with the upgrade, but all good after a clean install (had to upgrade first to get the 10 license key)