I haven't used the DAV before, but I do know enough about the design and topology of the two units to say with good confidence that there isn't actually a whole lot of difference between the two (DAV and DMP3) from an electronics standpoint.
With the exception of the chasis and the power supply, they probably cost roughly the same amount of money to produce -- although, to be fair, a giant like M-audio is going to realize some per-unit cost savings due to volume and scale economies.
But a lot of people really seem to believe the DAV is something special. Which I'm sure it is, because the design, components and topology are all good and should produce a very good, clean-sounding mic pre. The only catch is that one could really say the same about the DMP3, as it is very similar in all of those same regards.
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