OK, I bought a pair of these and have worn them for a few weeks now. Historically, I've worn thigh boards, Brown knee pads, PAW knee pads, and gone without any knee pads.
Some thoughts:
I love how these are designed to be mounted. You can tie them either on to your pants or to your pads, there are tabs for both. I chose the pad mount and am glad I did. If you look at the photo, you can see how they tie on. They "float" on elastic when they are tied to the pads. This allows them to move with your legs better, so they tend to stay on instead of being mounted too tightly to your pads. I feel like this protects better, and during game play they definitely stayed put.
Here's a front view:
And a side view:
Protection - These stay in place, and protect well against pucks and sticks. I feel MUCH safer with them on. I've taken a few pucks to them, and a nice jab & slash from a stick, and not a scratch on my knees.
Bulk - At first I thought they might be like most knee pads...too bulky for my taste. After wearing them, they're actually very flexible and comfortable. Once I got them strapped on properly, they pretty much disappear during play, which is the best thing I could ask for.
I'm ordering a second set for my other pads. These are the first set of knee pads that I can actually say that I like! Every other pair I've worn, I've discarded after a very short period of time. I think these will stay!