Well, to be honest, Saw 4 is definately আরো gruesome because of the Jigsaw's autopsy, but I think Saw 3, at the same time, is better. Because, the thing that makes 3 আরো interesting is that Jigsaw dies, and the killing still continued.
If আপনি like John and Amanda, this film would be for you. It's emotionally gripping (me and my sister cried at the end of it)the traps are also extremly gruesome.
saw 3 is but all the films are good the traps get better with each film so I would recommend buying all the films and watching them from beginning to end. Including the new one called jigsaw