First things first, I have bony skeletor legs so many of my issues wont be a the same for average Joes or manly meat heads.
No matter what I do, these pads rotate outward about 45 degrees and leave my inner shins wide open to injury. This is most likely due to me being bow legged, and all pads of this type tend to rotate a little bit. Fortunately for me I ride through dense city traffic and really only have to worry about getting side swiped or rear ended. So it's actually beneficial in my situation that these pads like to rotate outward. Being skinny, however, these pads only contact my legs at the ankles and the top of my knee caps. There's an inch gap between my shins and the inside of the pads. It makes no sense that the shin guard is designed to stick out further than the knee section unless the forward arching of the shins are supposed to flex inward upon impact, absorbing the blow like a spring. I have some big footballer friends and not even their shins stick out past their knees. In practicality this design works quite well for crashes but is also very uncomfortable since the ankle and knee cap are the only parts of my leg making contact with the pads. It feels like a constant pinch on my ankles and walking around in these can be painful after a while. While riding, however, this is not an issue.
My biggest gripe about this product is the crappy stitching quality. These pads are designed to be ridden by highly mobile, hard crashing, muddy and dirty adrenaline junkies. However, POC has the stupidity to use SINGLE stitching to keep everything in place. The first month of riding these without crashing, the stitching has already started to come out. I find myself every now and then cutting off loose strands that are 1-3 inches in length and having to redo the stitching myself. Unless you know how to sew with a fine needle, this sorta thing will seriously bug some folks. I wear with these pads 5 hours a day, four days a week, so they will see more usage than most, but for over $100.... c'mon POC, this is just lame.
I also own the POC bone arm protectors and they also have the same problem with the stitching. For the price, the quality just isn't there and the design of the whole thing still needs a lot of work. These knee guards feel like $70 pads... 90 at most.
The most important thing I must note about these pads is that they do indeed protect you and keep on truckin. The highly adjustable strap system is the best one I've come across after owning Six Six One and Fox Racing pads. Anybody can find the right fit after just a few minutes of tinkering with the straps. Once you get the fit just right, they will not move up or down at all....NOT ONE SINGLE MILIMETER that's awesome it is. These pads absorb blows like Mike Tyson taking a punch from a three year old. You can slam your shin into a fire hydrant or street pole at 20 mph and keep ridin without a hitch. I don't know about sharp rocks, but you can be sure you wont have to worry about your shins or knee caps in almost any crash. The agility you gain from the articulating joints is second to none. At full price, these pads will not fit the bill, but if you wait for a sale then you should certainly pick these up if they're in your budget.
Until a company designs these pads specifically for slim jims, you're not gonna find a better or more secure fit... so get them
UPDATE: I got sideswiped by an SUV blowing past a stop sign at 25mph. Not a scratch on me except my left knuckles where I punched out the jerk's headlight. I walked away just fine thanks to my knee and elbow pads.