Strawberry Singh has a video out on the Catwa mesh head. It covers the features of the mesh head very well. Her article, Catwa Catya Bento Mesh Head, provides more detail. Some of the minor problems with the head are touched on. Most impressive are the facial expressions (TM 12:00).
The last half of the video is showing the sliders at work.
Bento is still in Beta and a release candidate viewer is required to see Bento mesh items correctly. So, I think it is still too early to be buy Bento products. The designers have things yet to figure out, problems to find, and labeling to establish.