There are 2 things which mainly keep me with Dish. Multiple DVRs per account and TNT-HD. Cox cable allows only 1 DVR per account and does not carry TNT-HD. Yes, Cox is more expensive (~10/mo, comparing to AT120, but with a few more channels worth watching), but it would be with HD-DVR, and INHD1/2 channels. These ~10/mo would go a long way to catch up with $549 for 921, and by then we would be on MPEG-4.
At least with cable I can add/remove/upgrade/downgrade receivers and programming all the time without paying any fees. Dish DHA is strange as you can't (at least without e-mails to executive offices and/or playing CSR roulette) to upgrade receivers.
Cable's analog channels are comparable to Dish overcompressed SD. Locals on Dish are much worse then cable, Discovery, CNBC, and some others are better.
I'll probably stay until NBA season is over (at the same time my free 6 month of HD pack expire) and Dish plans with HD become more clear, then decide.