Ok, to give this guy his full name:
Tokina AF 80-400mm f/4.5-5.6 SD AT-X 840AF II
This is a very short initial impressions review. When I first started researching this lens I found very little about the new Mk II version, so maybe this will help someone.
The price gap between the decent cheaper stuff like Sigma 70-300mm APO DG or Canon 100-300mm USM and the mid-range options like the superb Sigma 100-300mm 4.0 EX and 50-500mm 4.0-6.3EX is relatively huge to the average punter/amateur; it's even larger when you next look at the Canon 300mm 4.0 IS L, 400mm 5.6 L and 100-400mm 4.5-5.6 IS L rung of the ladder. I'll leave aside the silly money stuff because I really don't care enough about photography to go there.
So, what are you gonna do? Keep the the cheap stuff or set the wallet alight with the bigger stuff? Well, what I did is take a chance on the brand new mark II version of the Tokina 80-400mm and initial impressions are pretty good I'm not gonna pixel peep here because I don't need to. I can already tell it will deliver decent results if I use it well, I ran several length and aperture tests, and it has no 'QA issues' that make me want to return it.
It's not as good as the L's above, but it is enough of an improvement to make it a great, cost effective upgrade from the cheapo stuff. Jury is out about whether it can compete with the Bigma, but at less than half the price even if it gets close I will be happy.
Build is typically Tokina and so it makes the L's look like the poorer, tho' trendier, relations from just a tad over the tracks. Design is old school for sure so we're losing out a tad in the who's coolest competition, but they are the only lenses than seem as solid as my classic old Zeiss and Pentax gear: think metal rather than plastic. Manual focus isn't L or EX quality but when am I gonna use that really? AF is typically a tad noisy, same as pretty much any none USM/HSM motor system. Who cares? Not me.
You get a pretty Ok lens pouch, built in adjustable tripod mount ring, lens hood, front and rear caps of course (front one is typically Tokina - cheesy!) a user manual, and I also got a free 7 year international Mac warranty. I paid less than £300 new

Filter Size is 72mm and, as you can guess from that, this really is an extremely small big boy zoom. You can see size compared against the 24-105mm 4.0 IS L, which is fine in all respects for day to day use. Dimensions (Length x Diameter) 5.4 in. (136mm) x 3.0in. (77.2mm). Weight is also very friendly at 37.0 oz. (1050g). So, if you want length and you want portable, even walkaround style, then this is a real contenter.
Of course, however small and light it may be we only want to carry the thing if the IQ is decent. There are plenty of super-light zoom that suck in that department so luckily my initial findings are favourable, actually better than I expected.
The previous model was well enough liked but probably not loved, with some reports mentioning CA and softness at 400mm. Again, hardly unique in a longer zoom, but we don't really want too much trouble from that kinda stuff. This is a whole new design with new coatings so Tokina have taken things seriously. It's not just a rehash.
This new model doesn't seem to suffer with CA, tho' I haven't pushed it hard and wouldn't normally anyway in real world use. It shows softness wide open at 400mm 5.6 but show me an affordable zoom that doesn't. I generally use a long zoom at f8.0 and by then this one is nice and sharp, requiring only the same two or three pass mild USM as I apply to my 24-105mm IS L shots.
At the opposite extreme is it pretty sharp wide open and firms up at 5.6, even more by 6.3. It's possibly intended for safari use, tho' I'm more likely to get another 50-500mm Bigma for that next year, so f8.0 isn't going to be an issue except for dawn and dusk shooting. Previous experience shows most of my shots aren't taken at those times so I am not concerned.
First shot above shows the 24-105mm 4.0 IS L next to the Tokina 80-400mm II, with the Tokina hood to the right. Second shot below shows both fully extended based on encouragement from a nosey pot plant and Cat. Yes, it is ultra-tiny for the range

Final shot below is the first one out the camera using typical 'me' long range settings, i.e. 400mm f8.0. I can't be bothered PPing loads of 100% crops. You can believe me or not
