[quote name='ThomBassmonkey' post='1175935' date='Mar 25 2011, 03:09 PM']I've used them both recently as well has having owned the 700RB-II in the past and currently using a 2001RB-II (and hopefully in the near future getting some MB/NEO gear).
MB500 pros: Smaller, lighter, slightly cheaper.
700RB-II pros: Bi-amping.
They're both designed to make similar noises, the 700RB-II is made with less constraints in mind but the MB500 does it's job perfectly. Don't underestimate the bi-amping though, although the basic purpose is to allow you control over tweeter volume from the front panel of your amp, it does allow slightly more control with the crossover buttons than I've seen on most cabs too. The boost control is part of the power amp (I like to think of it as a power amp gain) and should be relatively similar on both as that solid state power amp growl is what makes the GK sound (and why GK have decided not to make any all-valve heads).
I guess what I'm trying to say is that the 700 gives you more functionality and slightly more tonal options, but the MB is purpose built to be light and small and does that job admirably. If you need to be concious of size and weight or you're not using GK bi-amp compatable cabs, then the MB will suit you perfectly. If you're using bi-amped cabs and the size and weight aren't an issue, the 700RB will be the one.[/quote]
Thank you, that's just what I was after! I'll be using my existing cabs (a general mish-mash of Ashdown and the occasional Peavey) so the bi-amping/tweeter control function won;t be an issue... I think I'm going to go for the MB500!