I do not know the current class D GK amps, but I never cared for the MB-150. It's fine with an acoustic group, but I would not want it as my only stage monitor if anywhere a drummer with any hitting power - I wouldn't be able to to hear myself, even if the audience could through a decent PA.
I just thought there was neither enough power or lows to it.
Modern lightweight amps can have a LOT more power than that, and there are a lot of compact / light cabs on the market these days too. I'd second the vote for a GB shuttle head, I love mine. I do not know their cabs though.
Personally I use my shuttle on top of one or a pair of EA cabs - a little EA CXL110, which is certainly small but not very light, and a CXL112L, which is much louder and also bigger and heavier. I confess I've never tried the 110 by itself with a full band; don't know if it could keep up by itself.