These are blade properties that affect the performance of the blade. They are both equally effective given the application.
An aggressive blade has more of a cutting effect. These blades are designed to limit the amount of surface area coming into direct contact with the road. They are best for ice and snowpack when the goal is to clear as much snow and ice with the blade as opposed to melting snow with salt or brine.
A road friendly blade is designed to increase the footprint the blade makes on the road. The increased surface area on the road helps to extend the wear life of the blade. It also allows the blade to “glide” instead of “cut” which helps to reduce road damage, and to avoid obstructions like manhole covers and bridge joints.