I bought this lens from HK (via D-Rev), hence the price (I paid £1150, after reclaiming the VAT back from the seller).
Its a great lens for motorsport and wildlife. It is much more flexible than the big primes, and much cheaper than the Canon or Nikon 300 2.8s. For motorsport, the zoom is incredibly useful.
I use it with a Sigma 1.4 TC with no problems.
Due to the weight, I nearly always use it with a monopod (Giottos P-Pod). I have managed to learn to pan using a monopod, which isnt always easy.
I dont think it mounts all that well onto my D70 - there a very very small amount of 'play' in the connection, which is a slight pain.
If you cant afford a Canon/Nikon 300 2.8 and would like a lens of this quality, then I would recommend it.
If you have any further questions, please contact me. For examples, visit my website at
www.diesel-power.org.uk. In the 2006 gallery all of the pictures with a focal length over 120mm will be taken with that lens. One of them is a Porshe panned at 1/25 at 300mm (its in the Le Mans Classic gallery)
Anyway, i hope this helps.