I'm a bicycle commuter.  I do 22 miles a day year round and my legs constantly ache.  I had gotten used to it, but when I saw these I thought I'd give them a try.  I'm 68 inches tall, 175 pounds, very muscular.  I was concerned about the fit, as I have trouble buying clothes that fit.  Normally if I buy pants that fit my waist, I can't get my legs into them.  I bought the size 3, and it was a struggle to get them on, took about 20 minutes.  Slept in them last night, and woke up several times because my legs were overheating.  Other than the heat, they are extremely comfortable.  However, after sleeping in them for 8 hours, my legs feel incredible this morning, with barely a trace of ache left.  Maybe the heat helps recovery, I don't know, but I'm sold, going to wear these every night.  I just hope they hold up.

EDIT:  A couple weeks in, wearing them a lot, really do help, but the seam above the heel hole really digs into my heel and if I wear them too long it gives me a painful bruise.  I'm going to try wearing some socks under them and see if it helps.

EDIT (EDIT): The manufacturer instructed me to cut a small slit on the top of the heel hole to relieve the pressure.  I decided against this as I'm sure it will cause it to unravel...  They claim they will fix this in the future versions of the product.