I've used a Proto Switch E.L. Anti Fog Single, it tended to fog A LOT, although it was a mask that felt tight to the face, it was hard to communicate which I prefer in my JT Pro Flex Googles. Granted the Proto's were used. I had also previously used some camo googles from a friend and they were bulky compared to the JT Pro Flex googles, as well as poor with communication and were fairly hot to wear.
Light easy communication low fog quick to clean easy to customize and good 270 view
Only 1 I found was the earpieces which both tore but easily replaceable.
After wearing these googles to the field quiet some time and getting in some good battles I would say these have been my favorite googles I've come across. They are light weight, have yet to fog on me, and are easy to break down, replace parts, and customize. As I said earlier the only down side I've found were that I was a little rough on the soft ear pieces and they tore after a couple uses. Luckily they're easily replaceable and cheap to replace. I've heard the comments on the water between the dual lenses, and I've only experienced that briefly at home when doing heavy cleaning on my gear. Other than that no problems on the field and they give me a great field of focus.
They're a favorite google at my local field and I would definitely recommend them to anyone searching for a great google system.