I commute on a drop bar touring bike and split my time between the hoods and the drops. If I am riding in a headwind I will stick to the drops to reduce drag.

I have a Blackburn road mirror that velcros to the brake hood. I can't hold a line very well when I look over my shoulder, so I always check for cars in the mirror before looking over my shoulder. I wear eyeglasses and my peripheral vision sucks so that may be part of the problem.