Joe: I currently own two Nikon D7000 units with FX lenses and was considering an upgrade to the D600 mainly for increased low light performance on the full frame sensor. First off, the D600 does have a little more weight to it and a slightly thicker grip than the D7000. That initially felt good, but the bigger grip meant that the buttons weren't as easy for my fingers to reach without moving my hand off of the grip. Not good when you're on the fly. The feel of the body, in my opinion, wasn't as good as the D7000 either...that could be because of the thicker grip. One night thing about the D600 is that the mode selector on the upper left has a lock on it. You need to press a button down in the center of the dial before changing it. I have to admit that the mode selector dial on my D7000 has moved a few times after I've removed it from my camera bag. Not a huge deal, but now I'm trained to always check the dial before shooting...a good habit to have but the D600 helps eliminate that check. As far as low light performance, I didn't set up tripods to do "review" type of tests. My intent was to use this camera at weddings, indoor sporting events, etc. freehand where the low light cranks up the ISO. I visited a church, gym and other low light areas and snapped some shots. I used the Nikon 17-55mm f/2.8 lens on the D7000 and the Nikon 24-70mm f/2.8 lens on the D600. The low light performance on the D600 was marginally better in all of the shots. When you look at areas with high noise, the D600 noise was more "fine" like fine grains of sand whereas the D7000 noise was a little chunkier. Once I loaded the photos into LR4, I was able to apply noise reduction to the point where you couldn't really tell the difference between the photos. After applying the noise reduction, both photos only had small bits of noise. So....was the D600 better in low light than the D7000? Technically, yes if you're looking at the photos right out of the camera. Was it enough for me to upgrade to the D600? Not from the D7000. It was just too small of a quality increase to warrant the cost of the upgrade. They call the D600 a D7000 with a full frame sensor. If you have a D90 or earlier Nikon model and want to go into a full frame camera, then the D600 would definitely make sense. I am considering the rental of the D800 to see if that higher quality FX camera would yield even better low light results, but the turn-off for me there is that the camera takes Compact Flash and SD Card as it's dual card option. I've got a good collection of SD cards now so I'd be talking about a larger investment there. Not sure what I'm going to do.

David : If you are used to a D7000, you can use this camera without the manual. The image quality is outstanding. Although the camera is only slightly larger than the 7000, the FX format lenses are even larger, so that is where you will notice the size and weight difference. No spots.