I would have to say my Rule is a very versatile ball for me. It's a good "control ball" for me, as the reaction is very smooth. I can use it on a wide range of conditions, with surface adjustments here and there. I just put a little polish on it this morning, because I haven't been seeing the volume of oil I had been. I don't see much Track equipment over here (Okinawa), and can't comment on the Slash. I have Animal, Rule, X5.0 in the Track line so far. (I just need more money!!!)