I was wanting to try something new since my kyle strait's were looking a little haggard. I like that the VPD covers the entire front of the knee, unlike 661 which just covers the knee cap. The additional padding on the side of the knee offers more protection than the 09 models. I purchased the 09 model in a large and had to return them because I could not get them past my calf! Now the sizing seems to be on par with 661, although POC does not offer XL. My strait's have probably stretched out some so that is why I say they seem to be on par.
So far I have used these on two XC rides, 10 miles at Bootleg Canyon and 15 miles at another location. (I haven't gone down, so I cannot comment on how they held up after a crash). What I like about the VPD material is it seems to become more pliable the more you pedal. After a while you can hardly tell that you are wearing them. To help keep them in place there's a neoprene/rubber lining inside the pad above the knee. Like most knee protection, these things will get hot on climbs but will cool off on the way down. Overall I really like these pads and have only minor issues with them (tags sometimes pinch my legs, during hot XC rides they slip a little and nothing secures the pad below the knee). I hope this helps, especially those who tried last years model.