Additional comments on PVR functionality
The PVR DOES work, just don't expect it to be convenient to use. And keep in mind that, as far as I can tell, you cannot watch one show while recording another with this receiver - it only has one tuner for terrestrial stations, and another tuner for the satellites, and it only uses one of them at a time.
Just to add to the above: I have found that moving around within a program in problematic in any case, and moreso if you try to do it while the program is still being recorded.
If you are recording a HD source (terrestial or satellite) and you try to pause or go back in the program while it is still being recorded, the playback thereafter will often have "skips" in sound that make the show nearly unviewable (unless you have a very high tolerance for missing audio). If you simply pause it and wait until the show is finished recording, you will be able to play it back without audio skips provided you start from the beginning of the show, with one exception - every time you try to move around while the show is still being recorded, it seems that some data gets dropped on its way to the hard drive. I haven't decided if this is because the processor in the unit can't handle this amount of data I/O, or if the USB 2.0 interface can't handle it, or if it's a limitation of the old Maxtor 200GB hard drive in a cheapo imported enclosure that I'm using because it's the only spare external drive I had lying around. If others don't have this issue then I'd be tempted to blame the hard drive, however at least that drive works, whereas I've seen reports of some people hooking up newer/better drives that they say don't work at all. Speaking of which, the drive MUST be formatted as FAT32 before you hook it up to the receiver, THEN you must reformat it using the receiver's format function (which takes only a second or two).
If you are recording a standard definition show, then it seems you can move around in the show even while it is still being recorded, subject to some limitations. For example, once you begin recording a show using a timer or the record button, and THEN pause it, there is no way (that I can find) to go back to "live" viewing while you are still recording - you have to stay at least a minute or so behind the "live" broadcast. If you get too close to the point of recording, it will start skipping, and may go into a playback freeze (like pause but harder to get out of). This is not a big problem except that there may be times when (for example) you pause the display to answer the phone, determine it's no one you want to talk to, and unpause it within several seconds. At the next commercial break you might want to go back to "live" viewing (skipping a few seconds of commercials) but you simply can't without stopping the recording, as far as I can tell (keep in mind I've only had this unit for a little over a week, so I'm still learning things about it).
The pause button (if used when you have NOT already started recording a show to the hard drive) has its own weirdness, which you will discover 30 minutes AFTER you pause a show, if you then try to move backward or forward within the show. There is some kind of 30 minute timeout on pause, that makes pause all but unusable on shows longer than half an hour (however you can press the record button first, and then have better functionality, subject to the High Definition skips mentioned above). As I noted previously, pausing when you are not already recording doesn't seem to save a permanent copy to the hard drive, though obviously it must utilize the hard drive for temporary storage.
And speaking of moving backward or forward in a show... this may be the most frustrating thing of all. Basically that's controlled by two buttons, fast forward and fast rewind (there's also a slow motion button). If you use either fast forward or fast rewind, pushing once displays the program at two times the normal speed. Pressing a second time increases to four times the normal speed, and a third time is eight times normal. So far so good, but press it again and you are back to two times normal. So the fastest you can move is eight times normal. Now consider, you are watching a two hour movie and you are an hour and a half into it, and you reach for fast forward to fly through a commercial block, but you accidentally overreach the button a bit and hit the stop button by mistake. Now the ONLY thing you can do to get back to where you left off is restart playing the movie and fast forward through the 90 minutes you've already seen. A little simple math tells us that at 8x normal speed it will take you a little over 11 minutes to get back to your movie, which is probably a heck of a lot longer than the commercial break you tried to skip.
And that is a perfect example of what's wrong with the Diamond... it appears that they came up with a very basic feature set and then rushed the thing out the door, without doing any usability testing whatsoever. I have a 20 year old VCR that's probably faster moving around within a show than this receiver. Even if they'd just given a couple more speed steps (like 16x and 32x) it would have made a HUGE difference. Or if you could do direct numeric entry (press 90 and OK to go to 90 minutes into the show), THAT would be better. But I don't think any of the designers ever actually took this thing home and used it in their living rooms for a month or two, let alone gave pre-production units to "regular folks" to test.
Now, if all you want to do is record shows when you are not home and then watch them when you get home, you can do that. It does appear that you can record one show while playing a different one that you've previously recorded, although I haven't tested to see what would happen if both the show you are recording and the show you are trying to play are High Definition - you MIGHT get the audio skips during playback but I'm not entirely sure. I have no complaints at all about the audio and video quality (but remember, I'm still using the AV outputs going into a standard definition set - maybe in a couple years prices will be low enough on HDTV sets that I can finally get one, assuming the dollar is still actually worth something).
I think the thing that I find frustrating is that it's pretty obvious that the hardware in this unit is capable of doing almost anything you might want it to do (okay, maybe not "turbo" 8PSK, although we may never know for sure). But the problem is that the software developers got the software up to a very basic level of functionality and then apparently stopped development. To me this would be like getting a screaming fast computer and then discovering you can only run Windows 3.1 on it - no matter how capable the hardware is, you are limited by the software. Were this receiver more of a mass-market item, you'd doubtless have people out there disassembling the firmware and improving it. But instead, the few people who are talented enough to do that seem to prefer to selfishly concentrate on doing things which are illegal. That is their choice to make, and maybe their karma (or the big corporation they're stealing programming from) will kick them in the ass someday for staying on the dark side, but it shows how much things have changed since the early days of personal computing, when we all had to help each other use our equipment to its fullest potential.