On getting a FF (5D Mark III) and looking for a replacement to my EF-S 10-22, I have become a Zeiss convert with the Zeiss 21mm. The 16-35 just disappointed on the edge. The TS-E 17 is likely a good Canon choice and may be on my shopping list. 14 not so much for that price. So while the Zeiss 21mm is MF, turning for focus-assist is quite fast and the shots - amazing. And I dont really miss the zoom. When I need something wider, I'll look at the Zeiss 15mm.
For best IQ, 24mm Prime, otherwise the 16-35, which is really an excellent lens. I use both, and love them!