I've sampled quite a few knee pads over the years. My go to have been POC pads for a number of years, always M; around the time Joint VPD System pads came out I started looking for an alternative. I like the style of pads with a sleeve that goes over the quad. Sweet Protection were good but hot and not super pedal friendly. Leatt Airflex Hybrid fit nice and snug but the rear opening behind the knee always bit and the stitching started coming apart quite soon. I've eventually settled on Fox Enduro but the stench has made me continue looking. So I tried these.
The first impression is that these are a larger Medium than everything I've tried thus far. This is especially the case around the knee/quad where the fit is akin to a Large in other brands. This makes them slightly loose at the sleeve (so the sleeve slides down easier than other pads I've used) and the extra volume in the knee makes for a squishy, noisy pedaling sensation.
When you first put them on and go ride, initially they feel great (aside of being a tad loud). The fit around the calf is fantastic, benefitting from the strap which is fairly unique to these. The lower part of the pads stays firmly in place. The upper part starts to slide. When that happens the mesh starts chafing the back of the knee. The chamois I wear has long inseam so if I tuck the pad sleeve under, it helps keep in place. This a fairly hot solution. but helps with overall fit.
I haven't crashed in these, yet, and hopefully never will (right?), so I can't say how well they stay in place in a crash but my impression is they will do a better job than most.
If I did squats to boost my riding, maybe that extra volume up top would be spot on, but I don't. Overall the pads are very good, if the sizing was more typical I would rate these as pretty perfect so I'll give 4 stars.