I've been using TViX R-2210 PVR for a couple of days. I installed a 500 GB Western Digital hard drive, which the unit quickly formatted and now reads and writes to flawlessly. There is no discernible difference in the picture quality of live HD and recorded HD programs. The time-shifting feature is amazing and works just as well as the service-provided satellite and cable boxes I've seen and used.
One feature I love, which I hadn't read about, is the program guide. Like
TiVo and other DVRs, you can see a list of programs by date and time, select the program you want to watch or record, and the unit will turn itself on, record, then turn itself off again. I only have over-the-air (OTA) channels, which provide program info and short descriptions for most channels. I'm not sure how this feature would work with other HD services, but I'm very pleased that I'm able to do, with this PVR and no service, what my friends do with TiVos, DVRs, and expensive HD services. Of course, I get fewer channels (about 12, sometimes 15), but that's all I need.
One thing I don't like about the program guide interface is that, when you change the channel on the guide, the video feed changes channels with it. As far as I can tell, you can't look at lineups on other channels without actually changing the channel. Perhaps they'll address this in a future firmware update.
Another minor problem is that, if you switch back and forth between the TViX and regular antenna feed--for instance, I have splitter so that one cable goes to the TVix and another goes to back of the TV, so I can be recording one program on the PVR and watching another on through the TV's antenna input--the volume can be quite a bit louder on the TV.
The picture quality is fantastic! I only have a 32" 720 HDTV, but I assume it would look good in 1080, too. I set mine up to record in 1080 just for the heck of it. (a 30 minute show is a little under 3 GB, so you'll need a pretty big hard drive). If you don't have an HDMI cable when you initially set it up, like I didn't, and choose to use the included a/v cable, don't forget to select "load default" so that you can recalibrate the settings for HD playback.
This thing also plays music, displays photos, and plays a wide range of video formats, all of which you can transfer from your PC using a USB cable. The manual says you can plug USB devices like cameras straight into it, but I haven't tried this. You can also use the TViX as an external hard drive enclosure. There's an optional Wi-Fi adapter according to the website.
I was a little worried that, for some reason, it wasn't compatible with U.S. broadcasting and equipment, but rest assured, American consumers, it does work.