I had a 300 AF-I that I loved and sold to fund a D300. I just decided to sell some other things because I miss having the reach @ 2.8 and the tc performance. I am considering the Sigma 120-300HSM in this role. Think that's a good idea or am I going to be disappointed have gotten used to the wide-open quality of the AF-I lens. I can wait for another AF-I, but...who knows. I had a 300f2.8HSM prime and it never excited me although I can't say it was a poor performer. I know the Tokina ATX II and Pro are sharp, but they have CA issues and I don't know that I will have fast enough focusing for what I need esp. w/ a tc. I really don't want to sell a 200AFD micro to fund an AF-S I. Of course, I have to make the decision but I do respect opinions here, so...birds and wildlife...that's the application.