I have the 105 VR and it is a fantastic lens optically. If I had to do it all over again, I would buy the non-VR version, I have used them both and they are optically just about the same. The focusing is better on a D80 with the older non-VR version (the VR version REALLY hunts on a D80 and D40), but then again autofocus is something that isn't that important to me on a macro, since I normally manually focus anyway.
The VR isn't that important either on Macro, since it doesn't work well on Macro subjects.
On my D300, it the VR version does not hunt AT ALL. It is dead on accurate on autofocus.
Optically, the 105 VR is EXTREMELY sharp, it is the sharpest lens I own.
Then again, for $700 it SHOULD be sharp.
I prefer the 105 length over the 60's because I shoot a lot of bugs, and bugs like their space...
BTW another huge advantage of the Nikon over the Sigma (as you can see in the photo) is that the Nikon doesn't extend. It is rated as a 2.8, but in truth it is variable aperture at different focal lengths. Since I virtually always shoot at a high aperture to increase my depth of field, this doesn't matter to me.
The 105 also makes an extremely good focal length for portraits, for those people who don't want to be "crowded" by the photographer. I use it and my 50mm for that.
I have been using the AF Micro 60 mm 2.8D Nikon lens for a few years now and have received great result. I attached a photo I took just recently. It was shot at 1/80 sec. F-10.
The one thing I would suggest is, what do you feel you will be using the Micro lens for? This photo is of a stationary subject that will not crawl, leap or fly away. The longer lenses have an advantage when getting close to living subject.
Hope the resolution of the image is good enough, it's my first time at uploading a image to the forum being a NuBe.