I own the Smith Phenom Turbo Fan Goggle for about 3 years now. I have a variety of different lenses. They all do their job and I'm happy with Smith rather than going with Oakley like most other individuals. The only thing that I can say that separates Smith from Oakley is Oakley tends to lean more on the straight mirrored lens look that people enjoy, where someone can see a 100% reflection. I was disappointed with not being able to get a lens like that from Smith. Smith lenses are not a true mirror like Oakley can provide. Other then this style difference, Smith lens do the job of staying fog free and provide good vision in the conditions of which the lenses are required.
Performance wise, Smith gets an A-plus. I would have liked to see more of a straight 100% mirror lens like Oakley provides since its a popular attraction for most resort skiers and boarders.