Three of mine are tuner keys on top, two are two+two and one is three+two. I'm not sure how to vote to cover that... How the instrument feels and sounds is what I go by, where the tuners are on the bass doesn't really matter to me.
my current basses are 4, and 3+2. I prefer on a 4 string, 2+2. if it isnt a classic modle like a fender or a fender like bass. ie sadowsky, mike lull etc...
I primarily play 5s now, and that's a whole 'nother discussion because of how the headstock configuration can potentially affect the B string's tone. As far as 4 strings though, please give me that classic Fender headstock with 4 in line.