Having read about these the WHF, and having a Blu-Ray player that seldom gets used, I decided to import some of these, and have report the result is better than I thought possible. OK, I only bought 3 new classical discs from the Naxos range - The 4 Seasons, Chopin Piano Concerto No 1 and Mahler's 8th (forgot it was the one with all the singing in) . Silences are positively limpid, soundstage wider than I've ever heard it. It's like the pianist (playing Chopin) is there with you. As for detail, in the Chopin I swear you can hear the piano stool creaking during the difficult bits. The Vivaldi has an immediacy up with that of the seminal Jansen CD, but somehow with more space around it. Not just me who thought this, either. My girlfriend walked in and asked me what I'd changed in the system, it sounded so good. "It's almost like a 3D orchestra is in the room", she said.
The format is explained here http://www.whathifi.com/news/ultra-high-quality-audio-from-blu-ray-enters-the-mainstream . Naxos say this about it http://www.naxos.com/blu-ray_audio.asp , and here's a list of currently available titles http://www.blu-ray.com/news/?id=11097
These play on any Blu-ray player, and they come in Stereo and DTS (not sure what that is) mode. As far as I know there's no video component, apart from an on screen menu, but you can just put them straight into your Blu-ray player and press play.
I'm only sorry they've come so late on the scene. From what I've heard, they may be an advance on the regular CD, and I'm wondering how stunning the 5.1 DTS would sound.
Worth trying out, the format is genuinely impressive, particularly if you like classical.