When should I use a Locomotion Behavior?

The Locomotion Behavior will blend a set of motions to get the best possible animation based on the character's particle velocity and orientation. It should then be used when the motion to be played depends on these parameters (typically walk, run... but it could also be a bird flapping wings).

Contrary to the Motion Behavior, the Locomotion Behavior will not drive the particle, but follow it. It is then particularly well adapted for usage with Navigation / GoTo Behaviors or Maya fields (as the Motion Behavior would modify trajectories) but it also means that if your particles are not moving, the Locomotion Behavior will simply play a rest motion.