A couple of of tips, IMO, for what they're worth.
The inside of most good quality goggles has a very fragile film on them....NEVER wipe them when they are fogged up or you will ruin your lenz anti fog coating. Cat crap will not bring it back..
I fog goggles like crazy, Its my eyes that tear up more than most... puts a lot of moisture into the goggle. Also, the helmet you choose and your disposition to a sweaty head... some people dont sweat in their helmets at all while other are dripping. If you are prone to fogging you may want to look into one of the better ventillated helmets out there like the Klim etc... downside is that they are pricey.
One guy may like brand X and never fog them when another guy fogs them like crazy... depends on the persons eyes, the venting in the helmet, the fit of the goggle in the helmet, if they are getting a lot of pow stuck in the goggle etc etc....
I have had the best luck with the Scott 89 Xi goggles. They have a nose piece and are very well ventillated. They make a OTG (over the glasses) version as well.
The turbo fans work real well, but on heavy pow days they need to have the vent-foam cleared out too. You are looking at $150 for the fan goggles. Try
www.backcountry.com or
www.mgear.com for the fans.
Lastly, Get an underhood mesh google bag that you can use to dry googles in while you ride and keep one or 2 pair with you, if you are a fogger