I own two Whippen Stick longbows and I've shot both the Firestorm and Hellfire recurves up at Ken's place. They are both excellent shooting bows. If I remember correctly, the Firestorm has a little bit more deflex in the riser and the limbs are fairly typical of most recurves, wide and flat. The Hellfire has a little less deflex and the limbs are much narrower and thicker. They both shot really, really good but the Hellfire would be my pick of the two. The balance is excellent, it's smooth and quiet, the limbs are really nice and stable, and they are fast. I've committed to shooting longbows but if I go back to recurves I'd get a Hellfire in a heartbeat.
And, like others have said, dealing with Ken is just a pleasure. He is one of those people that really values his customers. Give him a call, you won't be dissappointed.
Chris Schwandt