Mind = Blown.
The MB cabs rock, I went with the ceramic ones because I thought the price difference was pretty big for 30 or so less pounds, and they're far lighter than anything I've owned in the cab department anyways. The cabs are deceptively large, I expected them to be smaller but they are almost the same size as the RB cabs. Not as deep, but taller I think. Don't quote me on that though because it's been five years since I owned my first GK set up.
The head is the new version of the 400-rb. It's a beast. Even through one cab it is incredibly loud, much much louder than the older 400rb and the BL600 (two gk heads I'm very familiar with). I use a very hot bass and I can't get it to clip, no farting out at high volumes, just beautiful, professional GK tone from this rig. I've been missing my old GK halfstack for years now, but I was so determined to find a tube set-up that worked for me. It wasn't happening. When I went shopping for my first real amp it was Gallien Krueger calling my name. Six years later, GK calleth me home.