Whip is much more worth it in my opinion (having been a pure 60 attack then transitioning to initiate 70 attack) I see a big difference in stakes, not only am I hitting more often, I have a whip which is much more accurate in terms of a d scim.
I am all for whip, especially in stakes that hint more of accuracy and 20+ str bonus is what you need to take out your opponent. A 70-95-1 would shred a 60-99-1 hands down.