I don't know...I can't really fully support every format until movies I would want cease to come out on the other. I have to say I've seen both and both look very good. Some times BD looks a little bit better, but on other occasions you'd be suprised to find the HD-DVD looks better.

I don't own either player yet, but I'm considering two things. One is to get the player that plays both. That way I'm covered. The other is to get the HD-DVD add on for the Xbox 360 and get the drivers for it to work on the PC, which in turn is outputted to the TV. That's pretty cheap!

As for upconverting players, most of them are junk. Most of them look worse than players set to output 480i. See the thread on scaling about that.