I had the sigma for my maxxum and loved it
it was a great lense for the money and plus it has the macro feature too
the zoom is fairly fast but a great lense for the money
For the money you have, I would look at a Nikon Nikkor 70-300 ED AF. A good sharp lens for the money. Nikon also has a 70-300 "G" lens that is not as sharp but about half the price. I have the ED and it's a good lens for packing light and having enough glass to reach out and touch someone.