I don't have to use a Bose Compact, but I prefer to in most situations. I always use two. I do stereo regardless of what sound reinforcement system I'm using. Even when I'm playing at home!
By the way, two of the guitar player/singers playing at Ernest's, after hearing my system for the first time, went home and ordered Bose Compacts. Both had been using big powered speakers, one Yamahas, the other JBLs.
For my situation, it doesn't get any better than the Bose Compacts, although the Nanos are VERY close.
I actually prefer their sound up close, but the Compacts cover the room a little differently.
If I were playing larger venues, I'd either go back to the full size Bose L1s, or check out the larger Lucas or other new line-array systems. Never again would I entertain the thought of using conventional speakers.
My criteria for a sound system: 1. Sound 2. Weight and ease of portability/setup time 3. Extra features 4. Price.
I can set up in 10 minutes, carry every piece of gear with one hand, and get it all in a fairly small vehicle with ease. Still, if it didn't sound great, I wouldn't be using it.