What a fantastic movie. It was recommended to me by a friend a couple years ago and just recently did I get around to watching it; if I knew what I was in for I would have definitely found time sooner! I would much rather have a film stay with you after the credits have finished rolling and Oldboy definitely does that.
It is a very mysterious movie and always has you guessing as to what's really going on. I worried in a few places because it seemed like it was getting off-track but for the most part it always pulled it back with sensical story elements, finishing off with an explosive and intensely emotional ending.
I only give it a 9 because like I quickly mentioned, there were a few parts that fell into the problem many Asian films have of not being coherent.