Well time for the windows outsider to chime in.
Out of the operating systems I have used the best that I can think of are Ubuntu 8.04/10.04, openSUSE 13.1, Windows 2000 and Windows 7.
Windows 7 is probably the odd man out in my grand scope of OS's, as a linux fan I see windows 7 as an actually very good OS that is stable, secure, fast and often quite reliable.
It reminds me a lot of windows 2000 my favorite OS in the Microsoft line, it too was often quite stable, reliable, secure and fast.
I like its use of the UAC, after the disaster in Vista over its UAC this was a big improvement (I only used vista a handful of times and if not set properly vista was annoying as all heck with its UAC)
I feel it runs smooth overall, not even touching my 4 gigs of ram.
But 7 has its downsides, it boots very slow compared to its contemporaries and aero can be very taxing even on decent hardware like mine.
Another I have with modern windows in general not just 7 is the constant and annoying reboots to get it updated, its a real pain too on a fresh install and I am often saying "what the hell!" often shaking my fist aimlessly as the shut down screen teases me about shutting down.
I would say 7 hits middle of the road for me, 5/10 if I had to scale it as while I do like it some of the quirks of the OS do put me off and make me wish I can boot back into linux a little sooner.
If it wasnt for the constant reboots I would probably rate 7 a little higher like an 8 but those reboots are very annoying for someone who just likes to get stuff done already as opposed to wait 9 hours watching a blue screen say not to power off the computer while the updates take a painful amount of time installing.
Erm... probably I went through that phase.
and a bunch of other stuff Windows 8 had ripped out.
