yeah... I think my mic-pre-thread-that-will-not-die pretty much covered this one...

(but please don't resurrect it..

)
I had the same exact thing as you. Behringer mixer running into Delta 44. I stepped up to the DMP3 and it was a better sound. I also tried the VTB-1 and JoeMeek MQ3 and didn't find either of those to be noticeably "better" than the DMP3. (actually, I thought the meek sucked,.. but I guess that's just my "taste"

)
For a "real world" (I guess) example of the improvement in quality that you would get when going from a Behringer to an DMP3, you can check oat my
NWR site.
The song "Tell Her This" was recorded using the following chain:
C-1 & MC012 > Behringer > Delta 44 > n-Track...
and the song "Better" was recorded using my new (at that time) chain:
C-1 & MC012 > DMP3 > Delta 44 > n-Track.
So, in other words, the only difference between the two songs is that one used the behringer mixer pres and the other used the DMP3. The C-1 was used on vocals and the MC12 was used on gits. I noticed that you're getting the MC12's for Christmas... so you can hear how they sound through the DMP3.
The song "Oh Holy Night" was done using my new pro tools rig (same mics though) and you can detect a quality improvement there too... (not that I'm suggesting you switch to Alsihad.

)
WATYF