I've had bad knees since I was 16 (hit with a fastball in highschool, broken rt knee, dislocated left knee one year later, scoped out chipped bits).
I can tell you, without a doubt, the the KT Tape works for me. Not just a product of mental trickery either. I was skeptical that just some flimsy piece of tape on my skin would somehow produce the claimed results, but the stuff works.
I first noticed the stuff on the beach volleyball broads, then saw some on pro tennis players, but when I started seeing it show up on some of the pro rugby players, I thought I'd give it a try to. Figured if THOSE DUDES bought into it, it must do something! lol....
All joking aside, I will tape up before most of my rides. Not every ride, but if I'm going out for my longer club rides, or if I'm gonna go tackle some heavy hills or do an extended ride of any sort, I'll tape up. I've even taped up for recovery purposes if my bones are really giving my some extra grief.
I can't vouch for the other two that were mentioned (never heard of 'em actually) but I buy the KT Tape all the time. Sports Authority, Sports Chalet....they usually carry it.