Joe,
Here is what this guy says over at AVS about it's short comings. How does this compare to the D1?
What doesn't it do?
1. The on-screen display (OSD) does not work properly using the component video output (at least with my TV). You can see it attempt to display, but it just flickers for a moment then disappears. Since the interface relies on the OSD this is a critical bug and prevents convenient use of the unit's functions. There is a work-around, which is to view the OSD through the composite video output, but that makes using the unit rather cumbersome.
2. You can’t directly select surround modes. You must cycle through them using single “surround mode” button. To me this is a major ergonomic shortcoming. Trying to do something as simple as switching between stereo and DPL2 requires the user to cycle through all of the surround modes. Couple this with the component OSD problem and it makes it impossible to tell which surround mode is engaged unless you walk up to the M15 to view the display (or switch to a composite input).
3. Can’t save separate channel levels for different sources, or for 7.1 chnl in. This makes it impossible to properly level match DVDA / SACD output to the rest of the sources.
4. Lipsync delay cannot be saved. I plan to by a new TV in the near future, most of which have video delay. Not being able to save the audio delay requires the user to recalibrate the audio to the video each time.
5. No bass management on 7.1 chnl in. Not a big deal because my DVD player has bass management, but I would have expected this functionality at this price.
6. Tone controls only affect left and right speakers. Not the wisest choice for a “surround” processor.
7. Tone control settings cannot be saved. Considering that most cable shows sound a bit wiry, I like to set the treble 2dB down and leave it there. With the M15, this must be readjusted each time. Another ergonomic shortcoming.
8. No tone controls for 7.1 chnl in. This makes it impossible to adjust for bright DVDA / SACD recordings.
9. Stripped down version of DPL 2. No Panorama, Center Width, or front to back fill adjustments. This is a big disappointment because I'd like using DPL2 to enhance some stereo programs.
Here is a link to the complete discussion:
http://www.avsforum.com/avs-vb/showthread.php?t=637503&highlight=NAD