Who has? Opinions?
Gonna invest in one for my AGV GP Tech...unless it's utter crap...
Ive used them for about 4 years they work really well no fogging at all, one downside is that sometimes the plastic nose bridge comes away from the neoprene but you can glue it back easily. its washable (they get dirty quickly)
a good buy if fogging annoys you!!
Most people seem to love them, so I'd pay more attention to them than to my mixed experience; on my Shoei TZ-R, the Foggy had a couple of issues and is currently sitting in a drawer instead of the helmet. Most notable was that I could never find a sweet spot where it wouldn't direct breath away from the visor and straight onto my sunglasses (I wear 'em routinely under the helmet), causing those to fog like crazy. Kinda defeats the purpose. It's too bad that the plastic nose bridge isn't maleable like the metal ones on surgical masks, since I'd bet bending it to fit closer to the bridge of my nose would do the trick. Hey, it occurs to me I ought to try the heat gun -- what have I got to lose?
I also had to cut the Foggy back considerably in a couple of spots so that it fit and I still could use all the cheek pad grippers in the helmet -- I tried it for a while with only two of the three cheek pad grippers (per side) attached, but the pads were just too floppy then. And on the TZ-R at least, there's not a whole lot of room in front of your mouth; I left the IZ_ velcro patch in the chin bar (since I'm still holding out hope i can make the Foggy work) and even without the thick neoprene in there the velcro fuzz touches my lips & chin all the time.
Still, your mileage will probably vary, and you're only out $20 or so if it doesn't work -- a whole bunch cheaper than a new helmet!
I've had mine for a few years now, but only need it when the weather starts getting cold. I think it works very well and was worth the $20 or so for it, you just have to move the flaps around until you figure out where to place them so that when you put your lid on you don't have any gaps between it and your cheek where air can escape. FYI, helmet is a Suomy Spec-1R Extreme.
Oh and side note: depending on how long your ride is, you'll have creases on your cheeks from the neoprene. :P
I use on all winter here in Seattle and I love it. Stops fogging (for the most part) and keeps your face warmer. I have Arai Astral X & Vector helmets.