I loved the movie, but like everyone said, there were some bits that weren't developed enough. I thought personally that the girls were very vapid before they landed in prison; sure, they were supposed to be innocent American girls but still...I felt like they lacked that bond that best friends are supposed to have. For example, in the montage where they're sight-seeing, the way they held each other for the photograph was very awkward-looking.
Then, there are some parts that were very ambiguous. I think it's pretty much understood that Danes' character didn't do it, but I can see how that could be confusing. Also, why did the camera dwell on Manat bearing a very grim expression after he put the bags in their taxi trunk? I thought it was suggesting something, but it turned out to be nothing.
Apart from that, the movie was great. I cried when Claire Danes took the blame; she's a GREAT actress.
Also, I wanted to see that bitchy Thai inmate get her ass kicked. Talk about lack of closure...