We've had our 2004 2720SL for almost a year and multiple trips, and on our latest trip (still going on, actually) we used the outside shower for the first time. I don't think the previous owners used it either.

I tried it out briefly before departing, and noticed that there were some minor leaks when opening and closing the faucets, and a much bigger leak from the seams of the shower head itself when the trigger was not depressed, but decided that we could live with it for intermittent use on this one trip.

The second day of camping, my wife turned on the hot water handle on the outside shower, and the whole handle blew off! We discovered that the plastic collar that holds the water handle assembly onto the camper had broken completely, and that having any water supply turned on to the camper at all caused water to promptly shoot out the hole. After much searching of local RV and hardware stores, we couldn't find anything that would even patch the hole, much less repair it properly, and had to use bottled water for the rest of the trip.

I ended up having to contact the manufacturer (ITC) directly for a replacement part: $18 for a new handle assembly, and $18 for a new shower head which I got at the same time. The lady I spoke to said it's a common failure, because many people (including me!) forget to flush antifreeze through the outside shower when winterizing their camper.