Although I absolutely, positively and without a doubt hated Windows 8 more than anything for the longest of times, I ended up using (and actually liking it). If you can get past the occasional annoyingness of the Metro UI, what you're left with is a pretty decent and very well optimized operating system. If you really hate Metro, you can get something like StartIsBack or wait until Windows 9 comes out, which won't have it.
I use windows 8 currently, but I am also acquainted with windows 7. I do like windows 8 to quite an extent, however, there are quite a lot of times when I do not know where a particular thing is placed. I end up googling for some of the simple things that are usually available right in front of your eyes in windows 7. I hate it when such a thing happens to me. The navigation in windows 7 was very easy.
This proves that when you get used to it, it's not a bad operating system. I do wonder though about it being heavyweight. I notice it can lag easier than my trusty old XP but maybe there is something I missed or they still need to work out the bugs. It's still quite a new operating system.
I use Windows 7. I switched from Windows Vista about 3 years ago, and I haven't looked back ever since. I think that it gives a smooth user experience and handles memory usage very well compared to Vista. I'm not upgrading to Windows 8 because I think it's not a great use of my money. I dislike the Metro interface (just boot to Start screen please) and also driver compatibility issues are a hassle.