I had trained for the '08 Honolulu Marathon and had been stymied by some IT-band pain once I hit longer distances. I finished the marathon way slower than I intended because of this but spoke with another guy from my training group who swore by his compression tights. I did some poking around and CW-X seemed like they were the most targeted and came with good reviews. A month after the marathon I was back out out running 5 milers in the tights with zero IT stiffening, and a week after that ran a 14 miler, again with no IT-band issues. I live in Los Angeles so I will be interested to feel the heat dispersion when it warms up but these have actually kept me a bit warmer on those mornings where its been in the 50's. While I had a small amount of chafe in the beginning, it does not take away from my 5 star review. Simply put, for me, these tights have been completely effective and I won't be doing any long runs without them. Now I just need to find some ultra-lightweight shorts w/o built-in briefs to wear over them (hey, I'm a modest guy).