It's a bit cheaper than the 16-35 2.8 II, but not significantly. Tokina must have something else up their sleeve with this lens. The pricing doesn't make sense.
It's hard to believe it would have better optics than Canon's 16-35 f2.8. It should probably be priced more on par with their own 11-16.
Yeah, i don't get this either. It's going to be extremely tough for the IQ compete with the Canon 16-35 II, especially when tokinas are known for CA and flare. i still love my 11-16, but this lens at this price doesn't make sense. For APS-C, there wasn't another super-wide constant 2.8 lens on the market, and it's a super sharp lens on top of that. It's a little more crowded in the full-frame arena.
About that 24-70 IS: does tokina make any lenses with IS?