I ride with a couple of similar Bell helmets, one of which has a visor (a Bell Slant), and the other doesn't (a Bell Solar). I cannot discern the slightest difference in my speed, or aero effect between them (As I'm a slightly overweight 55 year-old, I only average 15 MPH, but I'm sure I get over 30 MPH on some downhills). I CAN say that the visor is invaluable in bad weather, and in very sunny weather. And it does not impede my field of view when I'm riding on the drops. If I was buying another helmet, I would definitely get one with a visor.