I've been wearing a surgical sock (same idea as the sports compression garments) for about 6 weeks now, while I ride and afterwards. My needs are medical, to help the circulation in my right leg, which as of 10 days ago still had a pretty substantial blood clot (which is slowly absorbing and getting smaller, and will eventually disappear). The compression hosiery is highly therapeutic for patients like me in order to avoid post-phlebitic syndrome after a DVT (deep vein thrombosis, or blood clots) heals up. Post-p. syndrome is essentially scarring on your artery walls which hinders circulation chronically, you don't want that of course. But my experience with this has been very good, my leg really has been improving, and it responded to the compression immediately.
My recent positive experience with this type of garment for my medical condition and some of the stuff I've read about its use in sports convinces me this compression garb has to be helpful with recovery for athletes like runners and cyclists.