I don't know how it compares to the MBL or BAT linestage, but, I own a Ref No. 32 preamp. To me, it is a somewhat dull and lifeless sounding preamp compared to my current tube linestage. I tend to think the same way about ML amps -- they are on the "darker" side as well. I am sure the sound complements certain systems, so I certainly won't say it is bad sounding at all, it just doesn't quite fit my current system. I've kept it (its on loan to a friend) because it is VERY versatile, flexible, and ergonomically great (on par with the BAT and Boulder gear in those terms). On the other hand, gear from the same manufacturer is more likely to develop some positive synergy, so you may want to at least give it a try.
In other words, it would not be my first choice for adding a bit more life to the sound.
In other words, it would not be my first choice for adding a bit more life to the sound.