Which 70-300mm lens between the Nikon VR and Sigma?

I am confused about selecting a 70-300mm lens. I have 2 lenses to decide between, the 'Nikon 70-300mm f/4.5 - 5.6G ED-IF AF-S VR' and the 'Sigma 70-300mm F4-5.6 APO DG'. I hear lot of good things about the Sigma lens even though it doesn't have any VR and I wonder if the Nikon is worth the extra investment. I read lot of reviews about the Nikon too but not many seem unbiased.
I have a D7K.
Would appreciate your response.

Edit: I am looking at this lens for a little bit of wildlife and some portraits but all outdoor. I would mostly be holding the lens but plan to get used to the tripod.

Answer

• I have the Sigma 70-300mm APO DG.


• It's very soft in the 200-300mm range.



• I find myself constantly having to use high iso to get the needed shutter speed for hand held shots, whereas VR would help with this.


• It doesn't focus well compared to my other lens - its much slower (its not a USM type motor) and tends to hunt a bit.


• Shots lack contrast compared to my other lenses.


• Its relatively sharp under 200mm for portrait work, but for portraits nearly any 50 or 80mm prime is a better buy.

I'd look at the Nikon or even the new Tamron with VC that recently came out before I got this again. It feels like a steal of a deal at the price, but for me its not. If you're expecting sharp images in the 200-300 range (which you would want for wildlife shots), the Sigma isn't the lens for you.

Here's a sample from the Sigma, note that the feathers just don't look sharp.