I've gigged with my MB115 and it handled the cut-through better than an Ampeg BA115HPT. I have both amps, and prefer the GK. With that said, my XLR out and phones out are dead on the GK. I would imagine this isn't a widespread issue, but mine has been in a shop for over a week. GK hasn't returned any phone calls/emails to the service center (requesting schematics) in over a week
Now that I'm finished whining, I love the MB115. Once it's back from the shop, the Ampeg is going back in the closet.