I've built up 3 sets of wheels for myself using 819 rims. They are very, very strong rims, I'm 220+ and these wheels have taken some big hits. I run them on my hardtail and SS, and sometimes the rear wheel hits really hard when ya mistime something. I've got about 750 miles on my 819 combo on my FS bike. I went through a period of breaking spokes (build error on my part, didn't have a tensiometer at the time) and the wheel never went out of true.
The only con is they weigh a little more than some of the other alternatives. But after messing with the stan's goo a few times, it's a price I'll gladly pay. I rarely ever get a flat either, so that is an added bonus.