Hi - I borrowed a friend's S1 and tried it on a gig last weekend. I liked it overall. It almost seemed weird to just plug in one cable, turn it on, and the speaker/amp setup was done. I usually take a Nano 600 (Lucas) which is great, but a lot of parts and pieces. I'm not getting rid of my Nano 600 ... but I did order an S1 (via Frank at Audioworks CT).
The gig was ~60 people, a good sized room but only 1/2 of the room had the people (back 1/2 of the room was empty). Although I didn't get quite the bass my Nano 600 can put it, the sound was respectable. I really like stereo though (I know that's another whole topic!) so ideal I'd have 2 of them. It sounded amazing to me, given its size, weight, and being on battery. Did perfectly well for this modest-sized gig.
A friend used the S1 for a small broadway type show he played in, said it made it through 3 ~3 hour rehearsals on one battery change (I'm sure they weren't actively playing all 9 of those hours) - but still impressive.
I might even try the S1 once I get it, with the Emu Pipeline wireless rig, to see if I can go wireless to the S1. Not that setting up 1 cable is all that bad :-)
Jim