That guy from the puzzlebox, Pinhead

A group of my friends (My Ghoul Friday, Leigh Young and Mike Faille) have been slowly working our way through the Hellraiser movies. The strange thing is none of us think the movies are particularly good, but they're fun to watch with friends who share that sentiment. We've only made it through the first three so far. One of the things we've notice from the first two flicks is that Pinhead is not particularly good at his job. In the first movie Frank Cotton some how escapes the clutches of Pinhead and his Cenobite gang. When they encounter Frank's niece, Kristy, she convinces them to leave her alone because she can lead them to Frank. In the second movie they encounter Kristy in hell, she convinces Pinhead to leave her alone once again because she opened the puzzle box "accidentally." The creatively named female Cenobite, Female Cenobite, points out to Pin that it seems weird they keep "accidentally" running into Kristy and maybe they should tear her soul apart like they're supposed to. Tearing souls apart when people open the puzzle box is, after all, the only thing the Cenobites are supposed to do. Pinhead tells her "No we only do that to people who open the puzzle box on purpose."
Female counters with "don't you think its weird that in two movies we meet up with this Kristy person twice?" Pinhead just kinda shrugs and says "Hey it's not my problem, she says she didn't know what would happen if she solved the box. Let's let her off with a warning this time."
AND THEY DO!?
In the third movie Pinhead needs a certain number of victims in order to free himself from some goofy looking sculpture, long goofy story which I'm not going to relate at this time. He gets a guy to provide him with almost the number he needs.
Pinhead is one victim away from freedom but can't figure out that if he just kills the guy providing his victims he's free to go about his Hellraising ways.
It ends up the last victim the guy was going to bring to Pinhead kills that guy. Fortunately for Pinhead the last almost victim is dumb enough he can convince her to give him the dead victim provider thus freeing himself.

Anyway if you are a fan of the Hellraiser movies, could you please explain to me why they are so well loved? Is part four so amazing that they really needed to make four more after that one? Is all the love for Hellraiser based on the fact that the Cenobites in the first two flicks look kind of cool?

I'm sure some other horror franchises are more deserving of the love Hellraiser receives. Maybe we'll understand once we've made it to the end of the series.
Something tells me we won't.