I would get Looks over Shimanos, but Speedplay over both of them. I had an issue with the float of Shimano pedals that gave me knee problems. It wasn't that I need more than 6 degrees of float, but their is resistance in the float range. Keos move very easily too, and you can get fixed, 4.5, or 9 degree float cleats. Speedplay Zeros have 0 to 15 degrees of float, and you can adjust the float on the bike if you have someone help you.