I have seen every saw movie except saw 2 . Saw 1 was rubbish, the only gruesome scene was when he sawed his foot off, too much talking for my liking and quite boring.
Saw 3 was the best one out of the lot, a lot more gore and shocks, never boring. Some people watching it at the cinema fainted, that's how gory it was.
Saw 4 was very good, not as good as saw 3 but a heck of a lot better than saw 1.
Saw 5 was okay, not much gore compared to 3 and 4 but enough to make you go "Ewwww". You understand the other films a lot more after watching this one.