I have both and use both regularly.
The tube MP is good for snare drum, Bass guitar and the occassional tuba where the crunch of the tube at the peak of the transient works well. But it is noisier under most circumstances then the DMP-3.
The DMP-3 is nicer on voices,acoustic guitars and open room micing (such as percussion -flute-drum overheads) where it's quietness really shines.
I also have a pile of RNP / RNCs to compare them too. They each have their place.
tom