I've tested a DMP3; it might be the least expensive good stereo mike preamp available (and if not, then that honor would go to the FMR "Real Nice Preamp" in my opinion). It certainly meets my needs as far as input overload margins and phantom powering are concerned, and not very many "prosumer" preamps do so.
I had some email discussions with the designers while it was in development, and I think I made them aware that many modern condenser microphones have higher output levels and need more supply current than the microphones they had been testing with. The predecessor models DMP2 and DMP2 Plus had been deficient in both these areas.
The metering on the front panel is useful when setting up a system with test tones, but it's not peak-responding and it has narrower frequency response than the preamp itself has, so don't rely on it too much.
My one concern is that I don't know how robust the construction is--I once tried to record a concert with a DMP2 which had tested fine at home, but when I arrived at the recording site, one channel was completely out. The DMP3 isn't more solidly built as far as I can see than the DMP2 was.
Also, I believe that there is a "pin 1 problem" as in most equipment of this class; that makes the cable and preamp considerably more vulnerable to RFI than necessary. All in all this isn't a preamp that I take out on recording jobs, but I do have respect for certain important aspects of its design, and I would be very glad if I were to hear that other people are having good results with it.
--best regards