They strain their voices too much trying to sound good for my taste. I listen to vocal strain and breathing very well (was in chorus) and find them annoying. As for pure voice: Len Kasper, Dave Van Horne, Joe & Jack Buck along with Vin Scully don't strain their voices at all during calls and sound very smooth. The Braves quad follows very closely in sounding well, but they are too calm for my tastes and can put you to sleep.

 

Miller really strains his voice on plays at the plate saying SAFE! and Kuiper strains his voice alot when he is calling action like a throw from the outfield to home plate.

The best crew nationally doing games is Dan Shulman and Dave Campbell on ESPN Radio. Shulman has a clean voice that can ahndle calls and Campbell has good timing on his comments.