most people will sing the praises of drop bars so to be contrarian i'm going to list some advantages of flat bars:

1. most who commute with drops spend a lot of time on the flats. so unless you commute on the equivalent of chicago's lft drops are less necessary than most aficionados would suggest.
2. flat bar levers generally have better leverage and lessen reaction time versus drop-style levers.
3. flat bars encourage a heads up default riding position.
4. flat bars are twitchier and potentially more nimble (skills required).
5. track standing/sitting is generally easier on a flat bar. (i hate putting my feet down.)

installing interruptor/cross levers on drop bars mitigates many of these concerns. effective use of hood and drop position also mitigates some of these concerns. (i rarely see a drop bar commuter without their hands on the flats.)