Posting this from Windows 10 Preview running in a VMWare Player VM.
Not that far removed from Win 8.x which was not that far removed from Win 7 so all-in-all very similar to both Win 7 & 8.
You can now resize Metro (MUI) apps and clicking on the X in upper right corner actually closes the app as opposed to simply hibernating it as in 8.
A lot of people will be happy to see the return of the Start Menu. I still prefer to use toolbars as I've done since Win 2000 days.