I watched this film a few years ago on a plane somewhere, and I made the mistake of not watching it at the beginning of the flight and had the age old problem of missing the last ten minutes or so of the film, which is perhaps one of the few times you are begging the pilot to take a little longer to get wherever it is you are going.
I like the film a lot. I think the premise of it is something that is very unique, and has been filmed pretty well. What I like about it is the idea of memories, and how important they are to us, even if they are things that we want to forget. All things that happen to us in life have an impact upon us and we should cherish them because if we forget them then we may end up making the same mistakes over and over.
I don't quite understand the necessity of the plot involving the workers of Lacuna Inc, other than it perhaps highlights more succinctly that in destroying memories you end up making very similar decisions - although for me this is best left as a subtlety surrounding the main story. SImilarly the role Kirsten Dunst's character plays is important in the big reveal, but for me is probably unnecessary in telling the tale - including perhaps the idea that the big reveal is redundant?
Overall, worth watching if only for seeing Kate Winslet playing a more flamboyant character than Jim Carrey (that guy really can act!).