I've never seen any of these films because they never get shown on the tv to my knowledge, so I went and bought the Three film boxset for £20 8)
The first film is great, they did well for the budget they had, the second was awesome too, though the ending was a bit odd. Three was kinda meh, even though it's not really the same I found it to remind me of Friday The 13th Part VIII and Pinhead is a completely different person in it (ok I know he lost the Elliot part of him in II but he laughs like a twat ffs!)
I understand there's 8 films in total.. others being Bloodlines, Inferno, Hellseeker, Deader. They much cop? I have only seen Inferno in the shops...