Hm. I'm slowly moving over to the sip camp.
I think the thing here is that you'll pick whip when you see it anyway, and sip when you see that.
It's just that if you first come across both in the same pack, you'd probably pic sip unless you're just splashing for black and don't want .

I generally ignore Whip unless there's just no other good black cards in the pack. It isn't a strong signal for the color to be open, and there are a number of non-removal spells I would take over it.

Unconditional is good

Ideal black removal mix is a few Cures for the early drops, and a few Sips for the bombs. And the best black removal is the Gorgon. No space for the Whip in there. Theros is definitely not an environment when you want to be light on creatures, and with 18 lands, you rarely want more than four hard removal. I've had my Gorgon killed by the Whip + critter a few times, but I won those games anyway.