As far as desktop browsers go, anything that worked in Windows 7 works in Windows 8. What's in the "test stage" is the Windows 8 app-style versions of the browsers but those that run in the desktop mode work just fine.
The new app style programs work differently than traditional desktop programs, yes. Almost all desktop programs that worked in Windows 7 should work in the desktop mode in Windows 8. For example I'm writing this in desktop Firefox on a Windows 8 PC.