I saw this tonight. It's very much riding the wave of Saw, Hostel etc, and without any real understanding of what works. The first half is pretty boring and implausible, I saw the twist coming a mile off and the ending was a bit incoherent. There are one or two ideas but it really needed a lot more work on the script. I was expecting/hoping for a lot more psychological depth.
That said, Hostel wasn't very good either. I suspect the kind of people who go to these films will go to see for themselves regardless of reviews.