It seems very robust in the short time I have been using it. I really like the layout - very clean. I have both a suggestion and a critique however. My suggestion would be to have the capability to see a single muscle on the body, all others being absent. My one complaint would be regarding the side views - the hand is in the way! You need to make the hand disappear, and even the one leg, to be able to see the medial portion of each leg. Still a good solid app, maybe the best I have seen so far.
Chevyex about Pocket Anatomy., v1.4