I saw it about a year ago. Overall it was a good film, although I have to say that I enjoyed the dry cave and ice cave sections better than the cave diving. Hazel Barton, a British researcher who one of the leads (I can't remember the other's name, but she is a teacher from Georgia), does some cave diving in the Yucatan. As wil most productions that show cave diving it is BY FAR overdramatized. They show Hazel going through a tight restriction in sidemount gear, but the camera is in FRONT of her. Have you ever seen an IMAX camera? They are huge. Point being, it was totally staged shot to dramatize the diving. The science part of the movie was pretty neat. Overall it was wortht he couple bucks to see it (but there is an IMAX theater here where I live).
My .02 worth.