Flat bars are probably the best compromise.
Clipons allow you to lie flat on the tank, making you more aerodynamic which is why they are fitted to most race bikes.
Higher bars are more comfortable as the rider stays upright in the saddle. They also allow the rider to move his weight backwards and forwards more, which is why they are fitted to off road bikes.
Ape hangers are mainly for show, and can be painful without a back rest.
British Superbike School 