Weston revised the calculator dial each time. Personally I think the Master IV dial is the easiest to read, it's got a roulette arrangement. Once you spend a few minutes figuring it out, it's easy to decypher. The Ranger 9 is nice, but it's also physically larger so everything's a little easier to read (IMO).

My favorite comes from a Sekonic L-228 zoom. Big dial, easy to read numbers. I think it was highly influenced by the best of the Weston dials.