I have 3 questions;
1. Does Rain Gaurd work?

2. Why is Bushnell the only one to offer it?

3. is there anything on the market that duplicates it?

I own a bunch of Bushnells. In the rain or snow they all look the same as any other brand.
To me, "Rainguard" is simply marketing hype.

According to a recent article in the Rifleman comparing rifle scopes Rainguard really does work...

Even intentionally breathing on the eyepiece wouldn't fog the lens sufficiently to obscure the view through the scope.

Everyone has a "Gimmick", I think Rainguard is more than just a gimmick, but others will come up with their own version sooner or later.

I've often ondered if using Rain-X (I am a longstanding user of that product) on the exposed glass surfaces of a rifle scope would have a similar effect....

I just LOVE the way Rain-X works on my windshield....
and on my shooting glasses...

AD

If you like Rain X, try waxing your windshield. Same effect at a lot lower price.

Zeiss has something they call "Lotutec"
http://www.zeiss.com/c1256bcf0020be5f/Contents-Frame/62...67088525725b0039055d