Sorry to dredge up an old-ish thread....
I have my Maui Jims, and they are a little over 5 years old. Replaced the nose bumpers under their lifetime warranty, they didn't even blink.
My ones float in salt water, which is good, because I surf with them on, and they do fall off a bit. Just scoop them up and carry on (or wear a neoprene strap).
I replaced the lenses a couple of years back, from a place called thesunglassfix.com.au. I think they are based on the NSW north coast.
$70 or thereabouts for glass that was even better-specced than the originals. Several choices of tints and shade depths.
From memory, they may also do prescription glass, or cut custom shapes if you have odd/rare sunnies. I think for shapes, you send your sunnies to them and they quote.
Honestly, I wouldn't hesitate to use them again.