Supposedly VOOM reserved transponder space ahead of time for all of the HD channels, so there should be no overcrowding on HD transponders.
I compared VOOM vs. Dish on Discovery HD and I thought the VOOM via DVI had a slight edge over Dish on Component. HDNET does rock, I am always blown away by how pure it looks. OTOH, Dish was compressing the heck out of HDNET Movies for about 2 weeks. I sent emails to Dish Tech, Charlie & Mark Cuban and it quit about 4 days later. I am hoping my email had a positive effect on this matter.