Long zoom suggestions?

Would the 100-300mm APO be better in terms of IQ and AF accuracy vs the 300mm Tamron or Sigma in the under $200 price range?

What about if I try to save an extra $100, and go for the SIGMA 70-300MM dg os, or is that lens not much better than the 100-300mm APO or the others mentioned in this thread?

Thaniks