DirecTV since 1994; Echostar/Dish subscriber 1998-2003, currently have all the equipment still (SD receiver, 4 dishes, check out at least once a month for 'operation').
Having both side-by-side for several years, running to/through the same processing equipment and displays, I'd echo those who give DirecTV the SD edge; no HD receiver (E*) so can't compare there; almost bought one, but it would now be obsolete (no Mpeg4).
Have several friends/co-workers I suggested they go with them, simply because at the time they had foreign channels DirecTV didn't (but now has with their push the last couple years for 'international' carriage).
The biggest problem with them (and the reason I dropped what I had) is that they didn't pay good attention to what orbital slots they put their programming on, putting way too much at the 61.5deg location (great for the east coast but virtually not receivable on the west coast); until the got the sats up at 148 and
129, too much programming one paid for was not available, unless you managed to put that extra dish up (and sat was viewable).
This is the reason they got wacked by the FCC a few years ago, by 'splitting' local channels between different sats/dishes.
They lost their bid for Ka-band, by missing several FCC mandated 'benchmarks' (no money basically to pay for construction), so the huge increase in bandwidth DirecTV has been utilizing for almost 2 years now (with the Spaceways and now DirecTV10) they've had to overload the Ku/DBS sats they have with HD (sound familiar to the same bandwidth constraints at Ku/DBS with DirecTV?), but they have also utilized several Ku (non-DBS) sats to carry some programming (again, just like DirecTV), as well as yet more Ku/DBS sats, which means yet MORE dishes!
As far as DVR's and such, others have commented, but first, you need to receive the signal. I always remind folks, that most DirecTV customers require only 20degs of sky (99 to 119) to receive most signals (yes, some locals are over at 70 something and the internationals are at 95), but Echostar is 61.5 to 148. A range of 86.5degs. (Got your chainsaw handy?)
So, moving from Dish to DirecTV should be an extremely easy move; the 'main' slots at 110/119 are the same, all one needs is the small 10degs over to the 99/101/103 slots. Programming is, or shortly will, be about the same, unless they have some HD locals that DirecTV doesn't have yet.