did a great overview of QuickSync with IVB and showed how the performance and image quality differs from the HD 7970 and GTX 680. I use different software and the performance difference there is not quite as extreme as it is in Media Espresso, but I would say that the performance and quality difference in both is night and day. Obviously conversion time and how much this pays off will be based in your conversion profiles, I tend to shoot for 10gb video, 1080p rips with with DTS uncompressed audio which is gunna take a little while no matter what my approach is. For if its something not for my personal enjoyment, and maybe something my nephew might want to watch for instance, that I usually do at 720p, 4gb video, and compressed audio, in which case it absolutely flies through much faster. Same goes for converting something to enjoy on your phone or tablet device.
Incredible performance and and leading image quality aside, the best thing about Virtu technology and how it allows you to use QuickSync, is that your CPU and GPU resources are not being stolen. I can easily go off and play some games while it's encoding without a reduction in performance. Sure a core or so gets used up by the software itself, but most games are not that parallel anyway.