2: Unless you are really able to get your net out of the way, it is a bit cooler with no net. Which is great if you need it cooler. Those nets can really block the breeze, sometimes even if they are mostly moved out of the way. They can hold heat in also. Which might be a pro or a con.
This bears repeating...nets are hot, and noseeum netting is really hot. Going topless on a warm summer night with a bit of breeze is simply glorious.