All concerts, from rock to classical, from folk to Hip-hop, are done in MONO. In most venues, unless you're sitting in the 'sweet spot', Mono provides a better listening experience than stereo. The only one Stereo benefits is YOU, if you're a solo player. Stereo works best in home audio systems, studios, etc. Think about it; people sitting on opposite sides of the room are going to hear two different performances. Check out the best clubs on the planet and you'll find that their in-house system is mono. Having worked most of my on-stage life with a single leslie, a (mono) guitar amp (used by the guitar player), un-amped drums, and a PA system either in mono or stereo panned center, for the vocalist or horn player, all I can say is, it worked for us. Even monitor feeds for individual players will be a mono feed.

Never used one but seems to me the 'total immersion' effect of something like a multi-directional line array system would work best in most situations (and two of them would just be more of the same - just louder....and possibly muddier). Of course, there isn't a music forum on the planet where this (stereo vs mono) isn't debated ad nauseum, so why should SZ be any different. BTW, after thousands of hours of debate, no solid conclusion has yet been reached .

chas