530's.

One day I'd left my spd shoes at work. Rode in with casual shoes. Sucked, but worked. Didn't mind the flats at all, just would rather have been clipped in. Better grip would have been appreciated.

530s are lighter than 324s. Gonna guess the 530s are better, lower-profile in a pedal on the inside down while turning situation.

Was commuting on Speedplay Frogs. Liked them well enough, but spds are more universal and provide more than enough float. For me.