Having seen both, I would say this is not even a contest.
Kasia is absolutely outstanding, and will ensure you have a great time. She can cater for a range of tastes from fairly vanilla to downright superbly filthy
IMO, Anna-Marie was jaded when I saw her, overworked and going through the motions. Undeniably fit body, but this is not enough in the absence of any real enthusiasm, which you will get in spades from Kasia.