I posted my review of the Xbox 360 HD-DVD add-on drive over at AMN Tek, but I left out some of the technical mumbo jumbo. The review can be found here: AMN Tek
Anyway, for those that a few more specific doubts about performance, I’ll say a bit more here. From testing on similar setups, I can safely say that the 360 HD-DVD drive performs just as well as Toshiba’s A1 drive which is priced at $500. The drive can’t output at 1080p through component cables, but you can through a VGA connection. The problem is, however, is that most HDTVs accept DVI, component, and/or HDMI for their HD inputs. The 1080i resoultion is fine for movies, however, so don’t get caught up on the lack of 1080p support.
As far as sound quality goes, it is about the same as you’ll get with a decent DVD player. Unfortunately the drive doesn’t support any next-generation sound like Dolby’s TrueHD, because the Xbox 360 itself only supports up to Dolby DTS through an optical out cable. Still, the sound quality is excellent, but you don’t get the extra clarity of lossless audio.
The drive will push out visuals as nice as your TV will display them, so prepare to be amazed if you decide to pick one of these drives up. I still don’t know if HD-DVD is going to survive this silly format war with Blu-Ray, but for $199.99 I’m happy to enjoy it for however long it lives.