Used Tokina AT-X AF Pro 80-200 2.8 or new Tamron 70-200 2.8 for Pentax

I am upgrading to my first serious lens for my Pentax K10D and am interested in anyone's input on comparing these two lens or the new Sigma APO 70-200 APO 2.8.

I can get either of the Sigma or Tamron new for between $700 and $800. Since Hoya which makes Tokina bought Pentax they quit making the Tokina line for Pentax cameras. Hence, if I want the extra build quality and durability of the Tokina I will have to purchase a used one. I have found one on E-bay that is reported to be in Mint condition for about the same price as the other two lens I'm considering.

I would appreciate anyone with experience with any of these three lens weighing in on the topic.

Thanks,
Tim

Sorry no-one has taken up your question. I haven't used the lenses in question, but as a general observation I would be more confident of pentax lenses than alternative brands. Now a Pentax 70-200mm f2.8 is a rare and expensive thing, but if you do find one it would be brilliant. £2000 new if I recall correctly.

Of Tokina, Tamron and Sigma that would be my pecking order of choice.

Thank you for your reply. I can't afford the Pentax version of this lens, so I have to go for one of the alternatives. I read a response from one person who said he had some focus problems with the Tokina on his Pentax K20D. Has anyone else had problems with this Tokina on their Pentax?

The Sigma and Tamrons are just now being released in the Pentax mount. However, if anyone has used either of these others lenses on their recent Pentax I would love to hear your perspective. A recent review on the new Tamron said there were some focus problems on a Canon EOS camera. However, the Tamron was better optically than the Sigma in a comparison of the two lenses.

I would appreciate hearing from anyone who has used any of the three lenses.

Thanks,
Tim