Image Quality & Performance
This lens delivers amazingly sharp pictures with good support and long lens technique. Bokeh is unbelievable and really makes the subjects pop. I coupled the lens with the Nikon TC-20EII 2X teleconverter for the first few months that I had it. The results were good but not great - I felt that the compromise in image quality was a little too much. Upgrading to the TC-20EIII teleconverter made a world of difference; I stop down by 1/3 to 2/3 stop for an effective aperture of f/7.1 and the resulting images are tack sharp. Check out the detail on the Dragonfly's wings below (this is a crop of about 10% of the original image):
Eastern Phoebe with Dragonfly
This is also probably the fastest focusing lens I have ever used - it's fast, sure and is a dream to use. However, I rarely use this lens without the 2x teleconverter, and adding the teleconverter sometimes makes the AF hunt a little in low light. However, this and the Nikon 300mm f/2.8 are probably the only lenses that can handle a 2X TC with such ease.
Here are my contributions to the big VR argument - I haven't attempted a scientific test but from what I've seen, using the VR in NORMAL mode it doesn't seem to hurt the images any! How's that for a cop-out?! Seriously, the only time I switch off VR is when I'm doing video - VR makes it sound like you're shooting from inside your local laundromat.
This is one serious lens - both price wise and in the commitment required to use it. However, all this pales into insignificance when you finally snap that picture of a beautiful songbird in perfect focus with the background a soft, dreamy wash of color. For anyone who hasn't used one of Nikon's big lenses, here's my recommendation : rent one - you'll fall in love and eventually buy one!