Don't have Vista yet, nor poser 7 (okay so i'm behind the times? ROFL), however, I'm avoiding both, at least, for the time being.  I havent used either, though i've seen the good and bad of both splattered across boards from here to kingdom come.

The one thing that does make me hesitant, seriously, is my not-so-fond memories of Windows ME.   Yup, after less than a week, rolled back to WINDOWS 98!!    Since everything I currently have is working for me, i'm sticking with it lol.