The Good: Lightweight, soft, somewhat breathable in hot weather, easy to carry or strap to a pack, good for trail use
The Bad: Straps and velcro can work loose during a ride, and it takes a LONG time to break these in to your shape. It took me a few weeks of good riding until they really felt confortable. You have to take your shoes off to put them on or remove them.
I ride a lot of XC in rocky NH ( the granite state!) and wnated something to protect me on some really technical rocky stuff after a skiing injury left spme big scars on my knees. After the break in period, they are soft and confortable enough to wear for a few hour XC/trail ride even in the summer. Once in a while the velcro strap will catch on something and come loose, but the pads do stay in place well. If you are willing to invest the time to break them in, you will be rewarded with a light knee pad that could save your keens from some rock damage!