I have been running Windows 8 since the 2011 BUILD conference, the dev preview, then the consumer preview, then the release preview. So RTM wasn’t much of a jump for me. I have it installed on my BUILD samsung tablet, as well as on my work laptop.
While I have seen a few things not work, that would be expected, one is WinPCap (packet capture) software , which is an integral part of Wireshark. Turns out it doesn’t really work in Windows 8, at least the installer doesn’t.
What I had to do was run the install in “Windows 7 Compatibility Mode” and it then installed and I could capture traffic.
Steve Novoselac's Blog 