Long time lurker, occasional poster that switched from Dish to Directv almost a year ago. Here is my experience ... hope it helps someone that is trying to decide whether to switch or not.
I switched for two reasons, the number of HD tuners for TV's that I needed and the quantity of NHL Center Ice games in HD. We had an older Dish 722 HD receiver that I got when we first upgraded to HD in the living room back in 2007 (late to the HD game, I know). Then came the HD in the master bed, then one kid's bedroom, then the guest bedroom, then the garage. I had put off getting HD in any of the bedrooms since two of them had apple tv's which I used for game center live HD hockey (and could start games over while in progress), movies, etc.
Eventually it came time to upgrade and it was going to cost an arm and a leg to get enough tuners (at least 4-5) and HD receivers (5) so each TV was HD. I debated going with two hoppers (as 3 tuners wasn't going to cut it and we don't watch much primetime network tv), but as I researched and found out that directv's Genie and other HD DVR's could network together and create a unified playlist versus the Hoppers being independent (I know a Joey can connect to any Hopper, but not both at the same time). I also saw directv had the RSN's in HD full time which meant the NHL Center Ice Games would be in HD all the time. I don't know if Dish has since upgraded to RSN's in HD full time (instead of just the games and not all the games). Plus the fact that Directv unlocked the actual RSN channel for Center Ice was a plus as I hated that Dish would cut-off the game the second it was over and you couldn't watch the post-game show on the RSN as it was blacked out.
And like many, many people have said over and over again, if you like sports Directv is the place ... and it is!
Over all, the cost (at the time, and I'm talking full cost w/o the discounts) was a few dollars more per month for directv, but it is worth it to me. The cost for equipment was $300 less then what dish quoted me (a genie, plus 3 mini's plus another HD recv'r for the garage, which acts as a client for the genie when I want to play something recorded).
My experience so far has been very good. I notice a slight PQ edge to directv, but my main tv's are a 2007 50" Samsung 720p plasma and a 2008 42" Samsung Plasma (and all the others are smaller LED's). My sister and brother-in-law just switched to directv from dish and it looks much better on their newer 60" Samsung 1080p LED.
The obvious NHL Center Ice advantage is clear. All the games in HD (including games from Canada on CBC, TSN, Rogers, etc.) and I can watch them on the RSN channel so the post-game shows are blacked out. Even when they're only on the Center Ice channels they'll let them run through the post-game show and then some. I even get parts of the Roger's SportsNet post-game shows! So hands down this is enough for me to be sole reason I'd stick with directv.
The Genie System seems great and has lots of features the Vip722 didn't have. I have no idea how it compares to the hopper for features, but the unified playlist across all receivers is well worth it! I will say that I absolutely hate the Genie remote, to the point that after a couple of weeks I bought a couple of the old large white back-lit remotes (RX66B, i think) off Amazon for the living room and bedroom. With multiple devices I despised how few options the included remote had. The large remote is great and can even control my apple tv (as the apple tv can map any remote's output to its functions) and love the back-light. Wish the Genie and client's could take advantage of the RF feature of them ... but not the end of the world.
The clients do occasionally require being reset (average of once every 1-2 months) but it takes less than 3 minutes to reconnect. It seems to depend on how much you use them. I have two of them that have never been reset. The genie unit (HR44) has worked very well. It does occasionally hang for a couple of seconds and as long as my dad isn't over watching TV and controlling the remote everything is fine. It appears that when it does hang if you keep pushing buttons on the remote it ques the commands which further hangs the unit. Then "grandpa" keeps hitting buttons and the next thing you know it has to be reset (and takes approx 3-5 min to reset from an unplugging the power cord hard reset).
One other system note, I love the single wire system. So uncluttered and easy if you have to disconnect and move things. With Dish (has a 522 to go along with the 722) we had cables galore at each DVR!
The big surprise compared with Dish was the on-demand features (and this may no longer be true since I had a VIP722 with Dish). I subscribe to the everything package (or whatever it is called) and I love that just about every movie is available on-demand. I also like the newly added start over feature for some channels. I can't wait till they roll it out on more channels. I can almost cancel my netflix account (though not quite, there are still some much older movies/shows that netflix has that i love). I should note that I have Uverse internet that averages 20 mbps down so I have no issue with bandwidth.
The search and record features of dish was better, but I'm pretty much used to the directv way and it wasn't a deal breaker for me. Plus at the time Directv had Disney Jr (and the associated Disney HD channels) and I was tired of waiting for Dish to resolve their spat w/Disney.
So as most have said it comes down to what's important to them. For me the fact that directv has a unified playlist for all clients/rcvr's, superior HD RSN offerings (and the associated NHL CI package) and great on-demand offerings will keep me with directv for a long time. The only complaint is that they don't have GSN in HD. My mom watches my son and she loves to watch GSN and occasionally complains that dish has it in HD but directv doesn't. But she loves everything else about what i have and says it is easier to use than her dish 622 recvr.
If you've read this far thanks for reading and hopefully this helps those that are considering switching. I loved dish many years ago, but it seemed that a year ago Directv had left them in the dust (for what I'm looking for in tv providers).