It's okay.
It's the only OS that I've ever had bluescreen on me (3 times, and counting) but luckily I've never been doing anything important when those have happened.
Most games run fine, a number, however, are incompatible, and I've yet to find mods to fix this, though I've not been actively searching. (Anyone know of a way to make Crysis run on 10, HMU; or just reply on here)
It's far more user friendly than 8, though, I can effectively navigate it, it will be supported longer than 7- so yeah, all in all it's okay.