Speed
like others responding, I know people with both but have never ridden either. there are a couple of mechanical things to consider:
1 - the frame mounted faring does not add any additional forces on neck bearings - won't exagerate (sp) a loose or worn neck bearing problem (i.e. speed wobles )
2 - the frame mounted faring has the headlight mounted to it - like your cage, the headlight will not turn with the wheel for tight corners at night
a pro and a con - hope these help
When workin' on your ride the first tool out of the box should be the manual