I had my dtvrs installed on Wednesday and am impressed so far.
Although HD only allows one signal at a time you can watch a previously recorded show while recording another. SD allows 2 signals to be processed at the same time. The only issue so far was that I could not set two timers for the same slot. One timer can be set and then you can record what you are watching but it needs to be manually started.
Otherwise, two thumbs up. No glitches so far.