This is a great thread. I've been looking to buy a mixer amp myself for small pub gigs and presentations. Just to add that looking at the specs of the EMX512SC and the XR8300:-
In the UK they are similar price. I don't know if a one knob compressor is of benefit in a pub, but I'd rather have the toy than not. The yamaha (10 kg) is almost half the weight of the peavey (17kg). And its similar in layout to the old MG16FX chan desk I already own. On the other hand, I have never be able to break a peavey If the yam has something similar to DDT compression, its a tough choice.
