Tokina AT-X 16-28mm F2.8 Pro FX or Canon EF 16-35mm f/2.8L?

Just moved to FF and am missing my Tokina 11-16DX 2.8, a great wide angle zoom. I'd like to replace teh lens with a wide angle zoom. Advanced amateur not a pro. I'm deciding between a Tokina AT-X 16-28mm F2.8 Pro FX or Canon EF 16-35mm f/2.8L. The size of the Tokina doesn't matter much and my walk around is a 24-105L so the extra range of the Canon isn't necessary The Canon cost almost twice as much. Is it that much better than the Tokina?

thanks