We don't yet have a copy of Win8 in the shop. Purely from the hip, I don't expect there to be any issues, but you never know. If anything I'd expect potential driver issues. We'll set about getting a copy and running some tests.
Smaart v7 runs fine on my Windows 8 Release Preview, but take it with a grain of salt: we can't confirm full compatibility until we have an actual release build. Also, IMHO Windows 7 is superior to Windows 8. I hope you don't like the Start menu....