Atom is still way, way too slow for legacy programs, and that's supposed to be one of the "strengths" of x86 tablets. They may support them, but if they work slow on it, then it's all for nothing.
I haven't noticed a problem with Win32 desktop apps. It would certainly be too slow for something heavy-duty like the latest Visual Studio... But my use is more oriented towards Office, browsing and art software which it handles fine.