VTL 150 Stereo vs. MB185 monoblocks

Besides the obvious power difference and XLR input on the 185'S, does anybody have experience with going from a ST 150 to the MB 185'S.
What noticeable improvement might one expect.
Build quality differences? Does the 150 have Signature transformers?
The major gain you will achieve is an increase in soundstage depth. I tried out an ST-150 then went to the MB250 monoblocks. It was clear there was an increase in soundstage depth. I found this to also be the case when I went from a single ATI 1502 solid state amp into a monoblock pair.