JWT,
I just picked up a whirlwind last week to go under my One ball. I tried it out on medium oil THS, wood lanes with a hooking track. My ball is laid out for length and a control arc. The ball is an excellent choice for medium oil conditions. It has good movement but Doesn't over-react on the backends. It is definitely stronger than the tornado.
Charlest,
You're correct about the core, It is similar to the old Cat series (puma, savage couger and pantera) The roll is similar to those balls but with the coverstock being different. It gets decent length, reads the mids and hits hard like those old cats.
I believe that this ball is a sleeper, with all the hype Ebonite is giving thier new higher end stuff the Whirlwind is being overlooked. I didn't even think about getting it until I talked with my Pro shop Guru. He loves this ball and our styles are similar so I took his advice and went for it. Glad I listened.
Bob