Summary: I think I wrote a 4 star review when I first bought this lens. After owning it for some time, I have to retract two stars because of two main problems. The point, to me anyway, of having a zoom which goes to 300mm, is to be able to use that 300mm with no penalties on the issue of image quality.
Summary: I wanted to wait a while before posting a review of this because I wanted it give it a chance as other people have given quite positive reviews (which is why I bought it). I've taken the lens out in various light conditions and in countryside + city environments. Overall I have to say i'm disappointed, it's simply not as sharp as I would expect at any focal length. The kit lens that came with my D3100 is miles better. And I really have given this lens a decent chance.