I also have and love the Rapha Merino base layer both long and short sleeves. However the rapha mesh base layer, short sleeves and sleeveless, much better in the warm weather times. Plus in typical rapha fashion, they have cool sayings written on the front like "Sometimes you're the hammer, sometimes you're the nail" on the the short sleeves, and even cooler than that "Allumer la Meche" on the sleeveless which of course as all cyclists know, in French means "Light the Torch" and as the only thing more important than being cool is looking cool, this is priceless equipment.