Pitt has only beaten one ranked team all year (#15 Duke). They might have a better RPI and BPI than VT has, but they sure as hell don't have as many (or as good) quality wins.GT and Pitt have a better RPI and BPI, more quality wins and fewer bad losses than VaTech. Basically they have a better resume.
I haven't looked up GT's schedule, but I doubt very seriously that have more (or better) quality wins, either. I'll be mildly surprised if they beat any ranked teams at all, since they didn't seem to me to be very good this year.