I hear a little more in the low end on the MB2, and the boost seems to be a bit more potent.
The boost being more potent isn't surprising as Tech over on the GK forums said there was more gain in the boost control on the MB2-500 than other GK heads.
The bit about it having more low-end IS surprising. Initial reports made it sound a little lean in the low-end compared to other GK heads.

so i really wish you luck. 

