Bofh,
I've had an Esoteric DV-50s for some time now and shortly after aquiring it also had a unidisc 2.1 (I know Jim, you got the 'big one') so I can tell you quite clearly the differences between these two, FWIW they both were ran through a Linn Kisto at the time to a fully active Linn setup.
The 2.1 was a little more musical, but lacked some of the detail and separation of the DV-50, and the DV-50 clearly had deeper and tighter bass. Some might find the Esoteric to distinct, and some have said it's analitical, but I would not go so far as that. It is just more detailed than the Linn.
FWIW after a month or so with both connected, I finally sat the wife down to see her opinion, she preferred the DV-50 for it's detail and bass, while I could have easily lived with either, the DV-50 won me over too and that is still in one of my systems today... well actually it's on the counter as I had to try something else for a while but it's still in heavy rotation.
My 0.02.
KT