I Hopped in April after two long years with a very slow and unresponsive DVR. I did so in part for the Hopper, but in part because channels I wanted in HD are on Dish and not DirecTV.
The DVR has been almost perfect. There was a brief problem with one firmware version, but it was patched and fixed within a few days. The 30-second skip is slower now than it was when I got it. No idea why.
Some channels are not in HD on Dish that are on DirecTV (ESPN U, Disney, ABC Family, for instance.). And Dish has dropped AMC, Sundance, We and another channel I can't remember completely from their lineup. Since those channels don't matter to me, I'm still a happy camper.
Worth knowing is that if you are a pixel peeper like me, DirecTV's HD quality is better. Dish's is very good, but it is a bit softer. You will need a 1080 set and good eyes to spot the difference.
If you use an Antenna, DirecTV's interface has 2 OTA channels. The Hopper currently has none, and all indications are that when it does get a tuner, it will be a single-channel one. HD LiL quality on Dish is pretty poor for me, but I can't compare it to DirecTV since they don't offer HD locals in my area.
Would I do it again? Yes. Getting rid of my HR22-100 was terrific. Dish has met every expectation I had. And getting Blockbuster @Home has been a nice perk. A bunch of movie channels and a Blu-Ray disc out at a time for just $10/month.
The Dish fans will tell you that everything is better on Dish. I'm not in that camp. In some ways, I miss DirecTV for their professionalism and picture quality. But you could not pay me to use an HR22-100 again. Dish is different, and in some ways better, but in other ways not. You can always cancel in the first 30 days if it turns out to be horrible, and DirecTV sent me some pretty nice offers to try to win me back (which failed.)