[Closed] Sunglass lenses help

So looking to buy a decent pair of Sunglasses, but with so many lenses out there im rather confused.

I looking into the Oakley Flak jacket but what the differance between :
Black Iridium
Black Iridium Polarised

And is the differance worth the cost increase?

Also looking into the Rudy Project Rydons, again 2 types
Photochromic Clear ImpactX Lens
Smoke Lens

Help be great from those with them.

p.s Price wise the Rudy Projects with Photochromic lenses are about £20 quid cheaper than the Polarized Oakleys .