Don't know prices but this lens 24 - 85 is slightly wider angle faster aperture and probably better built worth a look $100 rebate as well.
http://www.nikonusa.com/template.php...productNr=2141
When it comes to the long lens most on the BirdForum seem to favour Sigma. Oddly I was on Andys site this evening admiring the quality of the robbin in his Sigma review. Now that picture is SHARP.
Don