Apprently from the threads there is not a very good reputation or impression of Palladia, the HD music channel. Personally I have really enjoyed in on the 42LH40 and Comcast, it seems to be what the store demos wish they could be. Black levels are good to my eye and sound is nice, with pretty good programming, from Iron Maiden to Sara Bareilles and Elvis Costello. They aren't spamming Soundstage, Storytellers is on from time to time. It's definitely clear enough to see sweat, makeup, and blemishes and see audience members in the darkness on the right shots.
My favorite was probably Dave Matthews Band at Piedmont Park, apparently only for sale on DVD and it looked fully 1080i to me, so unlikely to see it anywhere else at that.
There are no commercials and the only promos are excellent demos for the channel itself. I actually watch the raven movie.
To me it seems they have some good staff picking out premium HD content now and mastering it, FWIW. It's better than HD Theater.