The Yamaha will have much better build quality, lasting longer and being more sturdy, able to withstand the rigors and abuse of giging. It will most likely souind better too ..

i have the mg16/6 fx and mainly use it for my gigging setup (acoustic duo playing pubs and both singing) for this it is pretty good and sounds nice enough to my ears...for recording through the sound can get quite dense, if thats what you like...personally i reckon it gives a nice lo-fi kind of sound which may have its place in your recordings...having said that it is possible to get a clean sound out of it...i havent really tried it through my digi002r yet tho...still sussing out how it all fits together...id stay away from behringer tho...dont have heaps of trust in it..
Hey kurt- by the by, wats your opinion on DI'ing acoustic guitars as well as micing them (say a stereo pair of condensors, 1 dynamic and the DI) and blending the sounds? Just curious- did it a bit when I didnt have 4 mics (i still only have 4 argh being a uni student aint all its cracked up to be) and found the sound a lil different...thoughts?>
Cheers mate,
Hamish