Is that 3U? I'm still waiting for my Z-Force rackets to arrive. To be honest, I don't care that much for defense - it's all mostly about timing anyway, so it's less important if the racket is heavy etc - you just need to adjust your defensive technique. However, a head heavier racket will always create a more powerful smash compared to a head lighter racket if you can create the same swing speed and with everything else equal.The only disadvantage I can observe with head heavier rackets is with drive speed. However, even this can be mitigated/overcome with the right training exercises.