The Pro-Tec IPS Hip Pads are one of my favorite pieces of gear. They are a form-fitting base layer, with high density foam cells in all of the common high-impact areas (except the crotch, if you want crotch protection you will need to wear a cup under them). They are designed to protect winter-athletes from the dangers of park skiing or riding.
I found the fit to be excellent on my pair. The foam pads cover more of my hips and rear than similar products I have tried. I have taken several decent slams into rails and the ground I can attest to their ability to pad an impact. They obviously do not provide the same level of protection that hard ABS plating does, but they are have significantly less impact on your range of motion than similar products with hard-plates. It is really a personal choice as to how much range of motion you are willing to give up for the sake of safety. I find with these I lose no range of motion what-so-ever. Finally, these wick sweat very well where the foam cells are not present, they are not going to wick as well as normal base layer, but they do a great job considering what their primary purpose is.
My only gripe with these I have experienced so far, is that when sitting, the creases where the foam cells meet fold uncomfortably. After several days out they broke in and the problem has not returned yet, but it is worth nothing.
I cannot recommend these more to anyone who is sick of getting big bruises from hip checking rails in the park. I would certainly buy them again.