well the SC GB2R and A&H MixWiz 16:2 are extremely similar boards, so here's what I've discovered in my research: Just a little comparison for anyone who cares of two boards obviously competing with each other, I actually confused one board for the other recently.
-The MixWiz3 has some really interesting aux routing, and all six aux sends are 1/4" with two 1/4" stereo returns
-the GB2R has 2 1/4" aux sends and 4 XLR aux sends, with two 1/4" stereo returns.
-MixWiz has MIDI controllabe digital FX w/ footswitch mute jack
-GB2R no built-in FX
-direct outs are pre-fader on MixWiz [internal jumpers can change this to post, there are also a few other settings which can be changed via internal jumpers]
-direct outs are button-switchable pre or post-fader on the GB2E
-MixWiz has a Mono fader for controlling mono mix XLR output
-Mix Wiz has input pad switches
-GB2R has polarity reversal switches
-GB2R has a 2 trk return, assignable to the monitor section
-Mix Wiz has no 2trk return, MixWiz monitor section revolves around aux sends though.
Note: MixWiz1 had no FX, direct outs were factory defaulted to post-fader. MixWiz2 had fx, direct outs were the same. MixWiz mk3 has pre-fader direct outs on factory default. of course these settings can be changed via an internal jumper, but i've heard its not very easy to do.
The GB2R has that nice switch for switching the direct outs between pre and post, how nice.
The first two generations of the Mix Wiz had separate PCBs for each channel which of course makes them easy to repair.
I have too much time on my hands!