I have used a number of different compression calf sleeves, shorts and socks in racing, training and recovery and have concluded that for me the recovery benefits outweigh any race performance benefits. I do get a sense that my stride feels more aligned directly down the road or trail, less sloppyin later stages of a race or long run when using compression calf sleeves or socks . My favorite compression socks are the merino blend Swiftwick 12 which I posted about earlier this year. They provide a "light" compression and are great for fall and winter running, nordic, telemark and alpine skiing. I used them just about every day on our 100 plus mile trek around the Mont Blanc.
When its warmer out I often use Salomon EXO III Calf that I picked up from the iRunFar Store. Again light compression. The Salomons got me through the 13 miles of downhill in the St. George Marathon this year without the calf cramps I got in 2009.
I use compression shorts in training when my problem hamstring is acting up and they clearly let me run in less pain. Since I have gotten used to more minimal shoes in the last 4 months the hamstring issues have gone away... I have tried my Zoot and adidas TechFit compression shorts in racing and find them a bit too restrictive, especially later in races when my stride gets weaker and knee lift starts to escape me.
I highly recommend compression shorts for telemark and alpine skiing and find that they clearly keep my legs fresher day in, day out.