Real-world improvement,or just cool looks?

..many variables.
master cyl, & caliper piston size can make quite a difference
Later ('76) calipers are 2 3/4",earlier 2 5/8, '73 74 pin style e body also 2 3/4"
and i know of guys w/after market stuff that are not happy.
i have '74 E body pin style calipers on my Duster and am happy so far.