I have seen every single episode all three seasons. It is buy far my favorite show ever, I am sad that next week is the last episode though, but I am psyched about them going to Italy!
It is a train wreck and being so, that means it's that much harder to look away.. I rarely watch it though as there is always something else that I'd rather watch another channel..
Personally I have seen 2-3 episodes and I don't think it is that funny. I have friends who are always talking about how hilarious it is but I just don't see it.