First off, I've only used these once on a moderately chilly day (by Nashville standards) and second, I'd classify myself as a fifty-something who doesn't race but rides hard.
I wear a 44 shoe, so I contacted Real Cyclist per sizing and they recommended the XL. Glad I listened! The Campis fit nice and snug without being too much of a pain to put on.
Quality is good, and the zipper appears heavy-duty enough to withstand the rigors of cold-weather cycling. The thickness of the neoprene seems a bit thinner than the last brand I had (Performance) but I'm talking less than 1/16".
They're stylish and should do the trick for me this winter per keeping the toes warm. Besides, the price is killer!