After my year and a half as a Dishnetwork customer, I would avoid all of them and go with DirecTV.
Do you have any particular reason for picking Dish over DirecTV or Voom? Programming variety? Their "state of the art" equipment? Only have a clear view of the 110 and 119 satellite locations?
I left DirecTV for Dish because I thought they were better. The only positive was my first exposure to a DVR (the infamouse Dishplayer). I went back to DirecTV after they activated the second tuner on the DirecTivo. It was the best move I've made in the TV watching career.
Quality of service, quality of what's available, price, packages, discounts, rebates, etc. etc.
They just do it better and you get more for your money. Depending on your region, some people do well with DISH and that's fine, but I feel like every other person I've interacted with has just had terrible luck with them.
At the very least I'd say to you: Really compare closely the two brands and what they offer and proceed from there.
As a long time (5+ years) I have no problem recommending DishNetwork. I've had great luck with all of my receivers and the picture quality is better than DirecTV. My neighbor had DirecTV and was very surprised at the difference in PQ, so much so that he changed over a few weeks ago. There are pro's and cons with either provider, so you'll need to do your homework and audition both before making your final decision. As far as which receiver to get, that's going to depend on what you want to watch. The DishNetwork Model 811 is a HDTV receiver that can be used for DBS and OTA HDTV. The 921 is an HD-DVR. There are quite a few non-HD receivers to choose from as well. I would also suggest that you spend some time at WWW.DBSTalk.Com. Lots of really good info over there.
I switched from Dtv to Dish about 2 years ago. The reason I switched was not due to quaility issues with Dtv, but what was supposed to be the impending sale of Dtv to Dish. I also got a great deal to switch, 4 months free programming, free install, 2 free standard receivers and I upgraded the 3rd to a PVR for $99.
I found that uprading is very simple. I am expecting my 811 any day now.
If i have had problems with a receiver, a new one was shipped and the defective one was shipped back on their dime.
Customer service has been good, but not great. I did have an issue with a language barrier earlier this year, when talking to a rep. That can be very frustrating. From what i read Dish farms out some of thier CS to India.