Strictly speaking, ActivSkin and CW-X are targeted toward different users in the athletic arena, and so would not technically be considered competitors anyways. CW-X makes very high-end tights that use strategically placed bands to support joints and muscles in a specifically targeted way. While they seem to be a very good product, this level of performance comes at a price--around $100 and up.
ActivSkin full-support tights and sheer legwear provide non-targeted support more-or-less uniformly over the entire leg, in a slightly graduated compression that increases from thigh to ankle. The sheer styles also provide ventilation to the entire leg, rather than just specific areas. They are priced between $10 and $18 a pair.
While the targeted tension bands seem to be a useful innovation--albeit pricey--when it comes to ventilation we believe cooling the entire leg with a sheer material is preferable for runners and other athletes. I myself am a regular runner, although far from a competitive one. I wear ActivSkin sheer legwear when I go out for a run on cold mornings. (Of course, none of the current range of styles are intended to be worn without bike shorts or other running shorts). When I do, they provide enough insulation to ward off the chill that could lead to cramps. Yet, when I'm finished running--after the sun's higher in the sky, the birds are singing, and I'm sweating up a storm--I'm not overheated because the sheer nylon/spandex material breathes and cools while the perspiration evaporates. I also wear them when it's not so cold, as they provide leg compression without overheating on all but the hottest days.
I wonder if sheer leg panels is a transitional step in the process of eventually providing running tights for men with fully sheer legs--like those currently offered by ActivSkin. We see the state of the men's legwear market definitely moving in that direction, since we have been in the midst of it since the beginning.