Okay, this is my opinion only and it is based on a relatively short listening experience, so takeit for what you will.
I was looking for a preamp and saw that the LS 12 was being closed out by AR for~1495. I bought one without listening, the dealer didn't have a demo and I was afraid there availabilty was limited. After I received it I hooked it up and found that although it had a nice level of detail, it seemed to have somewhat diminished high end reproduction and a higher than expected noise floor. My delaer told me to "let it break in" but he also told me he would not take it back if I kept it for 1 week. I returned and listened to MF A3 friends house and found it to be very detailed and quiet. I did not think anything frequency was accentuated. I ordered it but then returned for an MF 308 without ever opening the A3.2. I think the A308 is the best sounding piece of equipment I have heard. So in summary I think th MF is considerably superior, and I believe that the best upgrade for you would be a 308(because you like the MF sound). The 308 can be had for~2100
