Foam cannons look cool, maybe a bit gimmicky, but cool. I am not gunna go run out and get one, but if/when one comes my way I'll check it out.
Dealership washes usually suck the big one. Years ago when I was getting the SLK serviced at the local Benz dealer they'd wash it, paint would always come back stripped of wax. After that I'd beg them not to wash it, but inevitably they'd forget and wash it anyway, one of the many reasons I gave up on dealer service.