I've yet to see Ghostbusters II and I'm not really sure if I should. The first is a classic, and I really wouldn't mind more of the same - which appears to be the biggest complaint regrading the sequel - but I'll probably cave one day.
My friend's father actually has a list of movies he's never to see. It's not required, of course, but said friend seems ok with following it. His father puts Ghostbusters 2 in the same vein as Rocky V.... I understand the latter at least. For that matter, I'm not sure why BttF pt 3 is on that list.
Bottom line, I find the concept fascinating and I'm probably going to do the same with my kids. haha