Of course the drop makes a difference, but you have to figure out what is best for you. If you've never had achilles issues, lower drop shoes have advantages. One big one is that you will build better ankle strength and flexibility, which generally leads to better push-off. If you're always going to be a heel striker because of size or body issues, low drop is not for you.
But most competitive runners of whatever age can benefit from lower drop. It's the #1 complaint I have with Nike. I think they artificially make high-drop shoes to please the masses, most of whom are just wearing them for fashion and not running.
I would love to know whether the Vapor Fly really needs to be 10% drop to position the plate in the right place, or just because most of their shoes are already 10%. I would prefer no higher than 6%, and preferably 4% for racing. I agree with others that the 10% drop artificially puts your foot at a steep angle, and for forefoot strikers, the heel is worthless. All it does is get in the way.