I agree with Scott, 124...the Korg PA1Xpro is probably fine with mono...Yamaha's stereo samples do not collapse well to mono, in my experience.

I must say, I do appreciate playing in stereo, not just for the better reproduction of stereo samples, but also, as you mention, to have the drums move across the stereo field.

Effects based on stereo also sound better, especially chorus, delay and rotary speaker, to name a few.

With two Bose systems, the stereo sweet spot is huge.

Ian