I'm on my second pair of these. My first pair wore out after 2 very full seasons of riding. These are so comfortable, that I wear them *every* time I go riding. I'll take them off if the climb is super long, but most of the time I wear them door to door. I love the confidence they give me for playing around on the trail! I've gone to my knees a couple times with these things on and they've done a great job of protecting me. They still look pretty good despite the falls.
I'm a little guy. My upper thigh measures 17.5" and my calf measures 15". The small size fits me perfectly and the pads never slip.
The first generation of these pads retailed for $150. I bought them at full retail and they were worth every penny. They're a steal now that they're down to $100 in my opinion.