I've been using two Compacts for several months now. I guess because I CAN. There was absolutely zero difference in audience response when I went from one to two, but I like it so what the heck.
I've also played a few times where I moved my stuff and took both Compacts. Setup time is still very short. It only takes about one or two additional minutes to set up the second system.
I also like the fact that if one system goes out, and have a backup plan in place. (Just use the other).
I will say this: I much prefer using two Compacts to one of the original Bose L1s.
DonM