Warning: strong opinions follow. (Flame retardant suit on!)
Well, I won't do a detailed post here. (There's so much info already here at SatelliteGuys as well as at DBSTalk's DVR-921 Support Forum and general Dish Network DVR Discussion.) Instead, I'll boil down my opinion of the 921 to three main points (and supporting discussion of each).
For those who might not read all the way through, let me say right off the bat that the 921 is a work in progress & these observations apply to the 921 today. Hopefully, a few months from now the only limitation which will remain for the 921 is that it only has one OTA tuner (and since it does have internal expansion slots, maybe they can remedy even this!).
Just got my 921 last night. I think the best things I can contribute are as follows:
Am I happy to have the 921? Hell, yes!
Am I sorry I paid this much (yes, I paid a few % premium over what it would have cost to get it locally -- if I could have bought it locally!) to be among the first dozen or two to own one? Not at all! Will I now be going to a great deal of trouble to run another cable so I can reconnect my 6000 as my primary receiver -- you bet! 
Well, I won't do a detailed post here. (There's so much info already here at SatelliteGuys as well as at DBSTalk's DVR-921 Support Forum and general Dish Network DVR Discussion.) Instead, I'll boil down my opinion of the 921 to three main points (and supporting discussion of each).
For those who might not read all the way through, let me say right off the bat that the 921 is a work in progress & these observations apply to the 921 today. Hopefully, a few months from now the only limitation which will remain for the 921 is that it only has one OTA tuner (and since it does have internal expansion slots, maybe they can remedy even this!).
Just got my 921 last night. I think the best things I can contribute are as follows:
- The 921 is not ready to be your primary receiver.
The notion that a $1000 box is not yet ready to depend on is hard to accept, but it is the current reality. Unless you live alone, don't even think of it. (In the first hour or two using it I could tell the 921 could be a real relationship killer!
)
Even if you do live alone, ask yourself what your tolerance is for things screwing up. Be honest - how will you feel if you miss the critical 5 minutes of that show because your 921 rebooted at just the wrong time. (No, I haven't timed it but I don't think that's an exaggeration. First it boots Linux, then it spends some time displaying the lovely "Acquiring Satellite" message and, if you happen to have been watching OTA you can expect to have to go back into the menu to force it to see OTA stations again.)
- The 921 is not ready to be your primary receiver.
...Especially if you want to time-shift OTA HD. (If you'll only be watching satellite, you might be ok with a 921 as your primary receiver.) Here's why I think that (unless they pour on the steam with lots of debugging right away) Dish Network will get their butts kicked once the HD DirecTiVo comes out or the cable companies really ramp up the roll out of their HD DVRs:
There are several reasons why people like & use DVRs. The one used most in the ads is "Pause Live TV!" I think this is featured because it is an instant differentiator from VCRs. This is handy, but anyone who's had a DVR for a while will tell you that easy time-shifting (using the program guide to schedule) is the killer feature. And right up there with easy time-shifting is skipping commercials.
Where does that leave the 921? Well, let's start with a few (IMHO reasonable) assumptions. First, the focus of the 921 is HDTV. Given the relatively small HD recording capacity (and relatively high price), that's what you'll mostly want to record). Second, the most time-shifting benefit comes where there is schedule conflict and/or little repeat within the week. Where is this most apparent? Prime-time network TV. HDNET or Discovery HD will air that show again... So will HBO or Showtime (and the commercial skip feature is moot!). What about movies, you ask? Sure, there's some value there. (IMHO, huge value if & when they turn on the firewire ports.) But again, throughout the week/month HBO, SHO & HDNET Movies will have enough airings that you may find a good time to watch without time-shifting. And let's not forget that DVDs can look damn good on many HT setups, providing most of the "start when you want, pause if you want" convenience of the DVR.
So I come back to my contention that (even though a satellite company may not want to hear this), OTA is where the most benefit will come from an HD DBS DVR. And OTA is where the 921 is most buggy! The biggest shortcoming -- no program listings for your local OTA signals. That means setting up timers for OTA is a real pain. And, no program names show up in your recording list. Either keep a "cheat sheet" of what you've scheduled to record handy, or expect to do a lot of back-and-forth to the DVR menu as you try to figure out what you have taped by sampling each show. (There's also the major bug with OTA signals which causes lots of reboots & other problems, but to be fair this is supposed to be a known problem with a fix soon to be downloaded in the L1.43 update.)
- The 921 is not ready to be your primary receiver.
If you don't have Dish Network yet, don't get it for the 921 (yet). If you haven't had HDTV yet, don't make the 921 your initiation into HD! If you already have Dish and you have a 6000 already (from what I hear the 811 still has its own set of bugs to shake out), consider the 921.
- If, that is, you have a love for experimenting...
- If you like being the first on your block (heck, in your state! ) with a new toy...
- If you like following (and contributing to) the progress of shaking out a new product...
- If you qualify for CBS-HD from Dish ('cause that's the only network HD where you'll be able to just select programs to record from the guide or see any program names in your list of recordings)... Or you can't get ANY HD over-the-air... OR you really, truly, (be honest now) NEVER watch any Prime-time network TV...
- And only if you don't consider yourself to be a newbie when it comes to this stuff!
Am I happy to have the 921? Hell, yes!
Am I sorry I paid this much (yes, I paid a few % premium over what it would have cost to get it locally -- if I could have bought it locally!) to be among the first dozen or two to own one? Not at all! Will I now be going to a great deal of trouble to run another cable so I can reconnect my 6000 as my primary receiver -- you bet! 
