I fix laptops and pc's all the time, do not upgrade to Windows 8, everything is backwards, its like some annoying tablet you don't know how to work. Stick to Windows 7 buddy, it's a lot better.
Performance wise, Windows 8 is faster, but if you don't have a touch screen and or a computer that can support a touch screen I would not upgrade. I've tested it when it was still in "Beta" and it's really hard to use with a mouse, mind you that is what I think, other people might think different.
I wouldn't suggest doing this, I have not heard a single good thing about windows 8. Everyone just complains about how shitty it is. Plus not a whole lot of things are compatible with it yet!
Unless the PC or Laptop you're upgrading is touchscreen, I wouldn't bother.
I upgraded, and I find navigation quite difficult and temperamental, but that's my opinion.
I am using Windows 7 and do not want to upgrade to Windows 8 as of now. I have always noticed a glitch in the software versions of Windows and when I was using Windows XP and then Vista came in, all the software installed was incompatible with Windows Vista and there were many faults as well.
I have heard a lot of bad things about windows 8 but recently I upgraded to windows 8 and it works very good. Just takes a little time to get used to it.