I don't know anything about battery types, but . . . .
If you haven't used a 18v dewalt, don't wait until after you have spent more $$ on the 9v makita to use one.
I used to have lots of the makita 9v stuff & I didn't think there was anything better. However, after using a Dewalt at a friends house, I never used the makita stuff again. The extra power & run time was amazing.
The only negative thing is the extra weight, but being able to drill 1/2 inch holes with out a power cord is nice.