As Andrew said, win7 + cubase 6.0 for me is rock solid. Might occasionally get arp sync/clock issues, they tend to be on projects where I am pushing my rig hard (100+ channels with multiple omnisphere instances, plugs on every strip etc). I'm still on 4.5 though and a little nervous to make the switch since I use my TI live but in standalone for my Lilt gigs.
Gotta say, theres nothing more satisfying then hearing your TI at full ball do a rate reduction sweep and hearing the entire PA rumble and groan. And big waves of applause afterwards
