So far so good. I've put Windows 7 RTM on several computers so far; a few upgrades and a few new installs. Everything is stable and performance is way up over Vista.
I'm starting to enjoy some of the new features especially in the task bar. I've installed both the x86 and 64 bit versions. Finally, the sound drivers don't skip in the 64 bit version. I can now feed my USB DAC from a 64 bit computer running Windows 7.
Media Center is now built into most versions and I really enjoy the interface. It even works well with a remote.