The upgrade itself is generally painless...... but using the crappy win 8 OS is not. You have to use third party apps or remember tricks and keyboard shortcuts to accomplish things you could easily do before. Not to mention you'll have no aero and some functionality to change network types (home/private vs public) etc seems to have been borked.
I'd stick with win 7 ultimate. No fuss, it will do what you want to do with no issues. That's well worth the cost.
I don't use any keyboard shortcuts,personally I tried Win8 beta so I knew what Win8 would be like before I upgraded to the official release version , took me about a week or so to get use to it.
I have everything within one or two clicks max on desktop via desktop shortcuts on taskbar etc..(ie not Metro) so find it very easy to use and customize,end of the day I'm glad I upgraded three Win7 PCs to Win8,I understand everybody has different opinions but all I can say is I 'm very happy with Win8 ,seems natural now.
I'll also say my desktop is neat and not cluttered even with my shortcuts,only have recycle bin on desktop,rest are on taskbar or Metro.
Learning curve is higher then Win7 due to layout changes etc but worth it if you have the time and patience(does not take long).
I use Win8 via mouse mainly,keyboard I use for gaming and passwords etc...
I don't even miss Aero or Win7 style Start button.
End of the day pricing,features and speed improvements over Win7 was enough for me to be happy with Win8 once I got use to the changes etc...
I forgot to say upgraded two desktop PCs from Win7 to 8,both painless and one laptop from 7 to 8 again painless experience in my case.