Buzzsaw is overall a much better variation than tempest.
The tempest spinny hat doesnt work properly, if you block an attack and its not even in front of you, you lose it. It would make more sense if it had similar properties to the ice clone in that respect, 4f spin is nice, but thats pretty much all you get from the variation.
The ex spin in buzzsaw is probably better, its advancing and multi hitting, still punishes alot of things other people cant.
The low hat gives you more screen control and makes strings like B22 safe, and the ex hats force your opponents to do something typically in your favour.