I have these sunglasses. This is the deal. The "Range" lens is for big faces, and offers lots of coverage. I wear contact lenses, so I especially like those lenses if it's windy out, in fact I've worn them while skiing and they give great coverage. More recently they came out with a "Blade" lens, they are huge- a shield, in fact. I don't think that is necessary unless you have some kind of special needs.
The "Pitch" lens is next in size and coverage, and has a convex lens shape at the bottom, which gives the more ample coverage. I like that lens also when I'm planning fast riding/ skiing. Lastly, and slimmest profile is the "Path" lenses. This is the lens you see more of in the peloton. Most of those guys have smaller faces. It has a concave shape at the bottom that gives it the slimmer profile. I use that lens too, but not as much due to my needs for coverage due to my contacts (too much air on my eyes = dried up contacts).
I obviously don't have any use for the "vented" lenses in any of the shapes, and I've never really understood the need for ventilation into your eyes. But hey, I guess somebody has those needs.
I hope this has been helpful to you. I love my Oakleys, especially my Radars, Good Luck