My absolute favorite base layer! It's so light and "airy" and can be worn easily under a jersey or vest - or can be worn on its own under a bib. Looks and feels great against the skin. The wild color scheme makes me very visible to surrounding drivers. I have all 3 colors!
I wear one of these for every ride. I ride in Utah where the temps can be in the 100's and in the 30's. I have found that it does keep me cooler in the heat and the extra layer in the cold is fantastic. I love it. It does stain though over time.
I was skeptical that an additional layer could keep me cooler, but being able to draw away sweat and spread it out does seem to help for indoor rides.