Well, after my eight year old computer died Thursday, I ended up having to change my plans. Got a new one, and as it unfortunately had that abortion Windows 8 on it, I did the upgrade to 10.
I'm fairly impressed, although more than a little annoyed in that you don't really have control over Windows Update any more (see wiklendt's post above). Also, apparently McAffee doesn't play well with Windows 10. It was pre-installed on my machine, and after it updated, the machine needed a restart. I decided what the hell and rebooted, and Windows could no longer start.
On the bright side, that was when I discovered the built-in 'Revert' settings. It basically re-installed Win10 from a partition, using factory presets. It meant I needed to once again re-install MalwareBytes, SuperAntiSpyware, Chrome, Steam, Office, and quite a few drivers, but it was awfully nice to have as an option. It also gave me the option of keeping my saved files or wiping everything. As a bonus, all the bloatware that came pre-installed by the manufacturer was gone, too. Gotta give MS kudos for that.
Interface-wise, it's a nice compromise between 7 and 8. You default to a standard desktop, but the Start Menu uses a 7/8 hybrid layout. It has a traditional start menu on the left for the most commonly-used things, and a Win8 style collection of oversized buttons for popular categories of stuff on the right.
I've not run into any incompatibilities yet, but I'm sure that'll happen.