I've used the Tifosis and I've used Optic Nerve's "Photomatic" lenses. I think the ON product is far better. I've had a couple pairs of Tifosis and have found them to be overly fragile. I have a pair of polarized ones in my car that never leave my car and get gentle use, but there is a coating peeling off of the lenses near the tops. My pair of Tifosi photochromics stretched out and didn't stay on my head well...then they'd hit the floor and the lenses would crack right out of the frames. Their range from light-to-dark is not as broad as the ONs, either.

My favorite Optic Nerves are their Neuro-toxin frame. I have a pretty small face and they fit me well. I actually have 2 pair--one with their photomatic lens and the other set I bought so that I'd have a set of clear lenses for really low light. I also had a pair of their Eyeque model (with the photochromic lenses), which I handed down to my 11 year old. He's not gentle with them and they have been pretty bomb-proof for him.