What server are you on? My own experiences (on Nightmare Lands/EU) are 95% good-to-excellent. Granted, I only PUG t1 FP HMs and I'm DPS, but, as far as I remember, I encountered only one quitter, and I do LFG HMs 2 times a day minimum after 1.3 hits, on both my lvl50 characters. Even if someone don't know tactics - he usually says so, and someone in the group always can explain it.