The fourth came out yesterday, which is when I went to see it. I enjoyed it, especially the twist that (SPOILER)Saw III and Saw IV ran simultaneously with eachother. I thought the test on Rigg was very similar to Detective Matthew's test in Saw II, as he just had to let people save themselves rather than intervene.

I enjoyed it, and there is going to be a fifth and a sixth. I though this one was definitely the most gross, and several parts made me CRINGE and look away, which I didn't do in any of the previous 3. Perhaps it was overly gross, but the story line alone keeps me interested in the movies.