I had this lens around 10 years ago. It was built very well, was reasonably sharp wide-open from 28-50mm but is kind of poor at 70mm.
f/4 brings everything up to the same level, very sharp from here on. I love this lens a lot and I bought another one recently because I missed it.
I shot photos for billboards back in the day with this on the D90 
I had the Pro II before and now I got the Angeniux-based one.

how about you guys, do you like yours?
I have the 3rd version (Pro II?) -- The f/2.6~2.8 with the bayonet lens hood. Wide open, I find it's weakest at 28mm, pretty nice in the midrange, and slightly weak at 70mm. Since I rarely photograph events it's one of my least used lenses. For casual or "freestyle" shooting I typically use a 24-120mm f/4, and for more planned events I'll typically use a 17-35mm f/2.8 along with primes and/or a 70-200mm f/2.8. I've owned quite a few Tokina lenses over the years. I had a aperture linkage issue with one (a 20-35mm f/2.

, and found that a second was not a good fit for me (80-400mm f/4.5~5.6 without tripod mount). But the others either gave me good service while I owned them (24-40mm f/2.8, 80-200mm f/2.

or continue to do so today (60-120mm f/2.8, 90mm f/2.5 macro).