My experience after several long and many shorter races that you sweat just under the cap, like a simple Nike baseball cap (which I have used in the past). The cap is closed broadly. While there are some mesh inserts for better ventilation, which affect the sweating but only slightly. The liquid can not be quickly transported to the outside. The shield begins much faster forward to dripping, as my old Nike cotton cap. Probably it is because of the better transport properties of the material.
What is much better but that it arises Weinger heat buildup. The old cap I had to lose weight partly because I heat underneath could not stand in the sun. With the cap I had not been like that.
The materials used are very pleasant, light and dry quickly. Before the sun you are protected at all costs. The size can be well set, and is sufficient for my relatively large head also completely. After the run, you can throw in the washing machine simply. It is also recommended to me the cap is completely durchgenässt after about 1 hour of running.