I think it's been getting better. Saw I had plenty of flaws, including some of the worst acting.
The first film had a fairly intricate plot, but the later films have really built on it because they've been able to have flash-backs to the earlier films. Especially after Saw II - I've just been listening to the commentaries for Saw III and it sounRAB like they sketched out the stories for III, IV, V and VI so they all tie together. Which is remarkable. There are few cinematic achievements like it, assuming they can pull it off.
I guess it depenRAB on what you are looking for. If you are looking for splatter-horror, then Saw isn't it. It's more psychological and emotional.