I bought these because I was looking for a way to wear knee pucks without putting on racing pants. They fit great, and they're a definite step up from the MX shinpads I was wearing under my riding jeans.
The only thing I don't like about them is the velcro. I don't like the pucks that come with the guards (they're too small, in my opinion) and wanted to use my Woodcraft Clucky Pucks. The velcro patches are so small, however, that they grab only one third of the hook pad on the back of the Clucky Pucks. The pucks still stay on, but I really wish the velcro pads were bigger. This would be a perfect product if they were.
A note about sizing: I'm six feet tall, and have the L-XL size guards. They fit me perfectly. Make sure you fasten the knee pads just above your knees when you put them on; they'll slide into place when you get into your crouch.
When you combine these pads with a pair of track boots, they form a solid wall of armor from the tops of your knees all the way to the bottoms of your feet. I definitely recommend these for aggressive street riding and parking lot hijinks.