It's been a few years, but I remember Tee demoing a Dave Matthews/Tim Reynolds Bluray for me when visiting him in Atlanta. He would go back between Dolby lossless to Dolby Digital. To me, the audio was a night and day difference and the video was simply stunning.
So for me, I have to agree with Zing. I think a lot has to do how the Bluray was transferred. In my experience, I think the Dave Matthews show is worth the extra coin over the DVD version, but I could see some other Bluray concerts falling short just like with some DVD concerts.