Well, the bigger lenses will give you more protection from the sun, and a wider field of vision that is actually corrected vision. But, I think I like the look of the smaller lenses better. That might just be because I can partially see through them (I hate looking at people with totally black lenses), and since you said the lenses will be black with either... I dunno. I still think I'd like the look of the smaller lenses better... leaves a little more of your face visible, which I think is nice.