not so good
we were issued thes during school of infantry and they were universally hated. Easily scratched, always fogged when you had to do something, and the legs constantly fell off
Best of Class
I've used eye shields from a couple of different makers. I have corrective lenses that need to be integrated into my eye protection. ESS ICE Eyeshields are absolutely the best of class. Comfortable, quick and easy to move the Rx carrier between shield lenses (clear, smoked, yellow). In the field and on deployment, these are my glasses even back on the FOB.
functional and cheap
I've been using these glasses in the field since i got them and it's a nice system especially for the price. The lenses change rather easily and i haven't had a problem with them staying together on hikes or whatnot. The only drawback i see is that the lenses tend to smudge up when you're changing them, if you have a oakley cloth or something like that to use it takes care of it much faster than the cloth provided, overall a good purchase.