I've tried Spy Happy lenses (Ace and Doom), Smith ChromaPop lenses (I/O7), Dragon (NFX) and Anon (M3), and while they're all good goggles and lenses, nothing really compares to Oakley Prizm. I have the Canopy's and O2 XL and the Prizm Rose lens is easily the best low light lens I've ever used; while my buddies were struggling to see in flat light, I could quite easily all the details in the snow. I've also used the Jade Prizm and Sapphire Prizm and they are also phenomenal lenses. As for the Canopy goggles themselves, they are very good quality and fit my face very well, and I've never had problems with fogging.
These are just from personal experience, but after using Oakley and being able to compare Oakley to other brands, I don't think I'll ever switch goggle brands.