It sounds better panned b/c it's more balanced and you get that natural chorus effect kicking in. Seems like the natural chorus effect jumps out much more when 2 guitars are panned opposite each other. As for live, I'd suggest staying with Mono, just b/c in a small club, the people are close to the P.A. and the people on the left side would mostly hear the 1 guitar coming out of the left cab, and vice versa..