HD DVD is much more of a complete package... the picture-in-picture video commentary, ethernet connectivity, etc. I have one and I LOVE it, but due to the difficulty of the fact that Blu-Ray has better exclusive studio support, I think that HD DVD is doomed to be 2nd place at best.
The detail in each seems the same but the color is different. HD seems natural while Blue-Ray seems sometimes more colorful or color filtered depending on the movie. Which is better? that depends on the movie.
LG makes a player that does both but it's pricey.
I thought Blu-Ray was ahead the whole time, but I remembered reading that it was the first time every in the 1st quarter of the year that blu-ray out sold HD-DVD. I'm not sure who might win, but didn't these companies learn from Sony? Sony had a great product called Betamax that was superior to VHS, but it's now gone. I wished they had just standardized the new format from the beginning
i bought the hd-dvd drive for my 360... i'll eventually have a PS3... so either way i'm covered but i hope HD-DVD wins though some of the studios to back bluray exclusively (who knows how much sony paid them) include disney (no hd dvd pirates for me) mgm (hd dvd spaceballs is out) fox (HD DVD Star Wars looks to be a dead dream) so the future is very uncertain
i guess we'll see which format the **** industry backs...