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.
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 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.
Very tight fit, 5' 11' & 174, 40" chest. Will return for XL