i can't say that it's better or not because i never experienced it. Aftermarket word is vast means alot of stuff in different prices some maybe better some not it depends upon what you want. Actually a shock should be reducing jumps in both direction, means it shouldn't allow the shocks to compress to it limits and shouldn't allow to suddenly comes back to it's original height.
in easy words without rebound damping you car will jump upwards after it hits the bump because shocks is reducing the downward movement but not reducing the upward movement.