I subbed to Dish for over 5 years. Couldn't get them to go below $699 for a 942. Had AEP and paid on time all the time. Got the HD-250 Tivo for $349 after rebate plus 3 R10s. You'll be happy you made the switch. Missing two Cinemax channels wouldn't be enough to keep me with Dish.
I also prefer using equipment that has been around a while. Tired of buggy boxes, and sounds like the R15 would put me back into that game instantly.