Okay, so after years of just hearing about this film and not seeing it (I have no excuses) I finally put it on. And wow, it's an absolutely fantastic film.
Ill start by giving my reason why I haven't watched for so long and that's because I was told it was really complicated and confusing. And I'll be honest, 10 minutes into this film I was completely out of whack. I had absolutely no idea what's happening. But after around half an hour or so it becomes really apparent what's happening and the story just becomes more and more interesting. So if you're worried about complexity of the plot. Don't, you'll be fine.
The ending as well I liked. You honestly don't know how this film will end, I was 10 minutes from the film ending and I still didn't know what was going to go down. But it's done really nicely and closes off any unanswered questions.
Watching films like Donny Darko you end up confused by the end and have several questions whereas this doesn't have this and I prefer that. (Donny Darko is great by the way, I was just giving an example).
Beyond that I thought the acting was really good, the managed to pull off good character development and the changes of memory were quite obvious so there wasn't any overlapping or confusion on what you were watching.
It's just overall an absolutely fantastic film and I highly recommend watching this if you haven't done so already.