I bought the Zoot compression sleeves for the calves (here on TE) and I wore them on my 4 day hiking adventure in the Grand Canyon. I didn't take them off for the 4 days. I still had LOTS of soreness, but don't know how much more/worse it would have been if I didn't have them on. They are made to be worn during activity. I don't know if I'm sold on them yet, but they seem like they might do their job. I think even if I'd worn medical grade compression I still would have been sore... I don't think anything could have made the soreness obsolete from that hike. Well, maybe new calves would have helped.
Now that I'm back, I'm going to use them when I run and bike. They do get a little hot (especially in the sun) and they are almost water resistant (water beads off them and they don't stay soaking wet).