I think there is lot of argument (some healthy) over this subject as there isn't really a 'right' answer that covers every aircraft type, runway and weather condition.
In no particular order, here are some of the things that might be considered on a bumpy day when choosing a land flap setting in a jet transport:
Advantages of lower flap setting:
* Higher Vref gives greater control authority
* Less drift angle
* Less drag, so better performance in windshear
* Often greater margin to flap limit speed
* More fuel efficient
Disadvantages:
* Longer landing roll
* More variation in speed due less drag
* Engines less responsive as lower thrust setting
* Easier to carry excess speed into the flare
* More energy into the brakes
* Tailstrike more likely in some types
Advantages of higher flap setting:
* Shorter landing roll
* More stable airspeed
* Engines more responsive
* Lower pitch attitude
* More time to adjust flightpath
* Minimises brake temperatures
Disadvantages:
* May need more control application
* Often close to limit/relief speeds in turbulence
* Loss of airspeed in the flare may need prompt action
* Less fuel efficient
If I was landing on a long-ish runway with a headwind component, I'd probably go for the lower flap setting. A wet and/or shorter runway, tail wind, high landing weight and/or high density altitude would have me fully configured. The books usually say I could land with either but I have a strange aversion to planning the use of a large percentage of the available runway if there is an option to use less...