There are two areas of concern for Windows 8: the new user interface, and application/driver
The user interface concern is pretty easy to get around. If you're not sure you'd like the Metro UI (Start screen) you can live your entire Windows 8 life on the Windows 8 Desktop, much like Windows 7 desktop. The key differences from Windows 7 is that is doesn't have the shadowy, translucent Aero eye candy (it's somewhat flat), but it works nice enough. And it doesn't have a start menu. There are scores of start menu add-ons by 3rd parties. Many are free. I paid 5 bucks for mine, Start8. I like Start8 because it is just like the start menu in Windows 7. It's a simple add-on and you can still go over to the Metro screen using normal Windows 8 commands and play there as you like. You might find some Metro apps to your liking.
The compatibility issue may require a little research on your part. If you have any special programs or applications that are specialized, or they use lots of hardware resources (like advanced games) you want to check online to see if people have had issue with them. On Windows 8 I use Mozilla Firefox, Google Chrome, LibreOffice, all with no issues. But I have not yet tried installing my Cakewalk multitrack recorder, so I don't know about it yet. I still use it on my Windows 7 machine. For device drivers
same thing: you want to check if the manufacturer has a Windows 8 specific driver. If they don't, the Windows 7 driver might still work (you want to match 32-bit versus 64-bit with your OS). Again, a little research may be needed. There's also a compatibility list at Microsoft's site you can check: Windows Compatibility Center: Find Updates, Drivers, & Downloads for Windows 8, Windows RT and Windows 7