Caught it this afternoon. Biggest reason I went is due to the positive reviews it's been getting. Some similarities to Oldboy, but pretty loose. Good bet it was used for inspiration on some level. Be prepaired for a slow-burn film (which isn't a bad thing). I knew this going in, but it tends to drag a bit in the first 45 mins or so. Once the second act picks up, it starts to move along, and before you know it, the films over. Honestly, by the time the big reveal came about, it was a little anti-climactic. I guess I kept wishing that something else was going to happen, but no dice. Still, if you're in the mood for a decent Hitchkockian suspense flick, it's worth seeing at the matinee price, and it wouldn't kill ya to wait for Netflix or other sources.
Just as a quick comparison, it's no Gone Girl or Prisoners, and definitely not Oldboy. Those being the only films I can think of in recent memory along the same vein...