Just today I had an opportunity to test a pair of $49(Campmor) Serengeti Paseo "drivers" sunglasses versus a $16 pair I found at Brigade Quartermaster, and a pair of ~$25 polarized "UV3" brand that is sold at rest stops and airports. I drive a lot for work and the windshield time facing east in the a.m. and west in the p.m. has me looking for a pair of sunglasses that get rid of my permanent squint.
While the Paseo was too small for my face, leaving a gap at the bottom, they were much, much better than the cheaper ones. The UV3 wasn't bad;they had a nicer fit, and they really are polarized, but the rosey-bronzey tint of the Paseo revealed a lot more detail both close up(looking at numbers maybe 100 feet away) and far away(clouds, and stuff on the horizon) than the more yellowish UV3s. The $16 ones are blades and have a really nice fit, but are noticeably darker and hence lose detail even though they'd be fine for very bright, direct sunlight.
The Paseo are metal framed and very nicely finished. The UV3 and the BQ off the racks are actually also very nice, plastic all around but ergonomic and seem to be pretty well made vis a vis the hinges, edges, earpieces, and not a lot of visible distortion in the lenses. Any of these three would be ok choices for a pair to wear and carry and not worry too much about losing a major chunk of change.
Campmor is running great deals on some Serengetis as well as Bolle, Julbo, and a lot of other good names. If I can find a pair that fits me better and offers the "drivers" tint that's the way I'd go. As of now only the aviator style fits and it's not quite right for me, so I may take the plunge and put up the bigger bucks to get exactly what I want.