YEAH ! This is a GREAT piece of glass !!! I love this for shooting action, animals and whatever's far far away ! Paired this up with a 1.4x teleconv ! ;p
Just curious, and don't mean to throw you off or something, why do you prefer the Tokina 12-24mm f/4 ? I picked the Tokina 11-16mm f/2.8 over the 12-24mm. This is really one good piece of glass. Comparison downside is that the range is more limited than the 12-24mm, but the aperture allows wonderful night shots. There's a discussion over at the Tokina thread section and I got the 11-16mm over the 12-24mm or the Sigma 10-20mm. All of these are like APS-C so it will be a cropped sensor anyways.....
Also, if you want the Tokina 12-24mm f/4, there's a DXII version coming out or already available..... I think it's faster focusing.