To each is their own but I personally found it to be all over the place when I watched it (which admittedly was a while ago). Character motivations and traits changed scene by scene, and the improv was hit-or-miss which added to these wild character and plot changes.

I remember when it came out there was some interview (I think it may have been Bale) where he was worried about an actor improvising a line that wildly changed or ignored some plot point. When he addressed it with Russell, he was given the answer of "oh don't worry we'll just adjust the movie to fit what you guys are doing". That's all paraphrasing but it gave me the impression that a lot of this movie was made up as it went along by the actors... and I think it shows.