I could hear a difference for the 251's, but not a $29.000 difference
It's a pity the mics and preamps need their own racks though. Now you have to use up 2 racks for a big (but beautiful) picture and two knobs instead of having this together like it was in the first previews (Slate Digital Introduces the VIRTUAL MICROPHONE SYSTEM).
I can hear a difference to but I don't think that difference is good or bad. What will be interesting is to see how this translates in a mix and how EQ, compression etc react to these "virtual" mics. Will they love them like the originals? This in turn may make mixing and recording a lot more efficient. The mic becomes most of the sound instead of going through your limited mic locker and EQing until it sounds good.