I moved over the MV 60 about a year ago after my old Bedini 25/25 decided to show its age. I listened to numerous integateds, as well as separates-- Bryston, Plinius, a used DNA .5, Blue Circle, Rouge and 2-3 other amps. It took me some time to adjust to the new sound, but I was never unhappy, just not sure what I was hearing, especially as I changed my entire system. Four pairs of speakers later, and a lot of experimenting with cables, I can say that the MV 60 is a great sounding amp. Natural, good sound stage, smooth and actually very fast. I like its bass response because it sounds like real music and not like a cheap car stereo or exaggerated. I hear live music weekly, so this is my reference. I do not want floor shaking bass, just accuracy.
But, here is the catch. IMO it excells and shows it true sound with "good or better" speakers. I have been using Meadowlark (Vireo and Kestral) and ProAc Response 1 SC, as well as several pairs of older NY Acoustic speakers -- even a borrowed a pair of Revels -- and kept questioning what was missing. These are all great speakers, so do not get me wrong. There is simply a "speaker hump" (so to speak) where this amp just shows it stuff and goes from lovely to fantastic.
I recently was able to get a pair of Penaudio Charisma monitors (coming to the US this winter -- www.penaudio.fi) and I was amazed. The system just came together. I think that the Charisma represents a new era of mini-monitors, and at 3K they outperform a lot of more expensive speakers.
But, to answer your question. You will not go wrong with the MV 60. The European reviews of the new SE version (option to use different output tubes) have been very positive. So, if you are looking at a used MV 60, the upgrade may be a great option to consider, as well as a chance to have CJ check out the amp. I suggest that you call Knut at CJ and speak with him. Also, please feel free to e-mail me off line if you want to talk more about this amp.