I used the 28-300VR on my D90 and now on my D800 and I find that I leave it on my D800 all the time. It has the range I like in FX for situations I come upon where I need flexibility. DxO rates it overall as a '15' on a D3X which is a 24mp that I use to compare to the D800...for whatever reason. I had to pick one and resolution seemed to be my quality measure...and DxO's I think. Anyway...the lens as a a 3.5 to 5.6 rates much lower in DxO tests...makes sense to me. My 105VR in comparison rates a '34' on DxO and my 70-200VR rates a '27'. So is the 28-300VR the best lens...not in my opinion...but is it the most useful with a high quality....I think so...and so do others. Rumor has it that Nikon will 'kit' the D800 with the 28-300VR.
Dan (Nikon D800,V2,Sony HX400V,Lumix ZS40) "I don't read, I just look at pictures" - Andy Warhol