Keep reading other posts in this forum and others. You'll find that people have done the measurements, and for SD & HD (especially) E* has better PQ than D*. D* is compressing, downrezzing, bit starving more. D* is accused of providing "HD-Lite." For today, the best choice is E*, unless you must have the Sunday Ticket, in which case D* is your only option.
All this can change in a couple of years.
The E* 942 DVR is highly regarded. The Tivo unit will no longer be pushed by D* as of October, and the contract ends in it's entirety in 2007. D* is moving to NDS DVRs, since Murdoch also has a controlling interest in NDS. No one has this new NDS DVR so there's no review available, but it's probably pretty good.
Both companies are moving to MPEG-4, so all today's receivers will be phased out over the next 3 years or so, starting with the HD customers. The 962 is the replacement for the 942. It's supposed to be essentially the same unit, except it also decodes MPEG-4. We should know more on both company's plans and products in the next 3 months. Or so.