In general:
ECE low beams are better at controlling glare to oncoming traffic (but not to same-direction traffic being overtaken on multilane roadways; this is going to change soon with a new test point)
SAE low beams are better at guaranteeing a minimally adequate seeing distance down the road on the right side; the ECE down-the-road seeing light minimum requirement really is way too low.
SAE low beams are better at controlling self-dazzle in bad weather.
ECE low beams are better at picking up pedestrians approaching from the left (this is changing with newer SAE beam distributions).
ECE high beams are better for seeing distance.
SAE high beams are better for beam width.
So which standard's better? Neither! Each has its strong and weak points.
