i have not used these but smith is pretty much all i wear for snow goggles and sunglasses. they make some of the best lens there is, along with oakley. but i can usually get deals on smith and that is why i choose them.
one of the reasons those glasses are expensive is the lens is real glass. to get this you usually pay 150+. the changing lens i assume would be fine, but ive heard from many people the prescription glasses that change to tint outside stop changing in about a year. so you may wanna just get the color you want and stick with that.
also one brand to check out, they will make the most durable and best lens is kaenen
i loved my pair till they sank to the bottom of the ocean. once i get extra cash flow i will be sure to buy another for fishing.