i may as well chime in here:
as a former owner of VSM-Ms and good friend of rcrump, he heard my merlin-based setup many times and saw it evolve from decent to good to great. but the inherent limitations of the design remain---and that is what he took issue with, and incidentally that is why i sold them. they are, after all, a 2-way, and cannot do BIG (and venue = big) properly. ---also, they don't like loud volumes, big listening rooms, or listeners above axis. within these constraints, they're wonderful. outside, and you get the suggestion for different speakers (with their own new limitations).
rest assured that my new SLs are not perfect, and there's many aspects of the merlins that i'd prefer over the SLs, they were that good (if ever i needed another 2-way, i'd buy merlins no question). but the SLs full range presentation and reproductive ease (with the right amp---no small chore finding it) are a nice change from the limits i associated with the merlins.
i agree with bob that a change in amp will not get venue from the merlins. a sub will. i know--i did this w/ entec LF20s and it filled in the bottom nicely. and like bob, i have to question the logic of trading one world-class amp for another...my guess is there's other system problems that would need addressed before upgrading a top 10 amp to another top 10 amp.
rhyno