I have been running PS3 media server v1.10.51 on the Windows 7 betas. It works perfect when transcoding mkv, divx, avi, dvds etc... I think also the network access to the shared folders is appering much faster from the PS3.
Keep up the good work and will post more about running this awesome program on Windows 7. My computer 3gh dualcore runs much faster and smooter than on vista.