Well there are only 3 to pick from: the LG BH100, the LG BH200, and the Samsung BD-UP5000. Of those I own both the BH100 and the BD-UP5000.
Hands down, the Samsung BD-UP5000 is the best combo player out of the 3. It's profile 1.1, supports all HD DVD special features, has a HQV Reon video processor which upscales standard DVDs better than anything I've ever seen, it can bitstream all of the audio codecs and can decode all but DTS-MA and output them via it's 7.1 analog outs.
My review here.
The LG BH-200 is similar in that it is also profile 1.1, supports all HD DVD special features and can bitstream all of the audio codecs. However it only has 2.0 analog outs so no high def audio without an HDMI receiver. It also doesn't have the Reon, but it does have the QDEO which is almost as good.
The LG BH-100 is a first generation player and it's only profile 1.0. In addition it doesn't support bitstreaming and can only display 1080p at 24Hz, not 60Hz (probably not a problem if you have a newer TV). It does have 5.1 analog outs though and can decode TrueHD so you can get high def audio that way. No way to get DTS-MA with this player though. Also, it does not support HD DVD's HDi, which means it doesn't support any of the menus or special features. It has it's own menu system that works pretty well, but stuff like PIP and Internet connectivity won't work. The only reason I got this player is because I got it dirt cheap for my dad and he only owns a few HD DVDs anyway and doesn't care about the menus or special features. It's not bad, but it's slow as a Blu-ray player so only consider if you can find it for almost nothing.
Pics of the guts and HD DVD menu system.