They do everything everyone has already told you they do.
You can whack away with a mallet, and you will be fine. So if you did happen to face someone that is 90mph+, you have nothing to worry about.
From a design perspective, the main thigh pad is rather big.
While playing normal straight shots, it does not represent any problem.
When playing the hook and especially sweeps, it is somewhat awkward.
If I could design my self a custom set, I would make the top quarter of the thigh pad a separate part connected by the material, so there is a joint that moves when I raise my left leg for a hook, or when I go down on one knee to sweep.
Even so, the thigh pads are seriously fantastic!
Any questions, fire away!