Maybe I will change my view on this after I get back into riding for a while, but when it comes to speeds, I have always been much more concerned about improving my speeds at the low end where aerodynamics don't play as large a role and at the top speeds, have enjoyed the more upright riding positions where I can feel the air rush against my face and body.

But that is also because I am someone who will trade off some speed for significant increases in comfort, so the improved aerodynamic positions that a drop bar bike allows, is not that big of a deal to me, certainly not with how uncomfortable I feel when in that improved aerodynamic position.