One of my favorite movies.
And a serious mindfuck.
I also like the fact that both films feature tiny parts for Simon Jones, the original Arthur Dent.
I also haven't seen 12 Monkeys, unfortunately. My experience with movies is sadly lacking, and the sheer number makes picking a good starting point paralyzing. (I still haven't seen Citizen Kane, which has been on my computer forever.)
I haven't seen the movie yet, and for the record? "Just like films" means nothing. Unless you're fascinated in the art of filmmaking - if you're a "buff" - it doesn't count. I have friends who "just like films" who watch The Notebook and American Beauty and cite those as "incredible films", and that just doesn't count. The people who really like films are the ones who get deep into them.
But I haven't seen Citizen Kane, so I'll withhold judgement.
While you will have to rethink the whole movie once you've reached the end, you are left with some sort of answer. Some of these movies on the other hand, like Memento, will make you wonder WTH really happened for hours and days after actually watching it.