MHDT Constantine vs. MF V-DAC, Beresford 7520?

I've been auditioning various Dac's for my HTPC based system.

I absolutely love the Musical Fidelity V-dac and was thinking that the MHDT sounded kind of dull compared to the V-dac, but...

Then I changed out the power cord from the generic one that came with it to home made Belden 83802 one that I have and WOW the MHDT opened up and since it is cheaper (used) than the V-dac I'm thinking I might keep the MHDT.

The V-dac has been powered by either a 13.8v regulated power supply or a 12v sealed lead acid battery. So I'm getting the most out of it.

Anyone else compare these two dac's?

I'm also waiting for the new passive output stage modded Beresford TC-7520 DAC to be available...Anyone compared the stock Beresford to the V-Dac/MHDT?

My system:

HTPC (low powered AMD based with toslink and SPDIF outs)
Nuforce IA-7 integrated amp - superb!
B&W P4 compact floorstanders - transmission line, 1s order crossover. Great speakers!

Signal cables IC's, homemade CAT-5 biwire speaker cables (nothing seems to beat these to my ears, and pocket!)

Rotel RCD-971 - soon to be retired :(
Rotel RT-955 Tuner - fabulous!
I have the constantine+ dac and find very little to fault with it. Is yours a current model or one of the non+ models? If it is the + model with the upgraded op amps i think you would have to spend significantly more to maybe get better sound. I have had mine for a year now and really love it.
Does the 12v sealed lead acid battery you mntioned bring a marked improvement over the wall wart PS that comes with the V-DAC ?