While I believe the D600 can take a terrific photo, I do not concur with the others that all cameras get this same amount of dust. While it is true that a camera will get dust, the amount and speed of accumulation with the D600 is phenomenally fast compared with other cameras. I went through three units spread out over 3 months. While some claim that they only see the dust/debris/oil spots at greater than f/22, I have seen them at f/5.6 and f/8. Now some folks live with their aperture between f/1.4 to 4 and they should be fine. Some do not.
One other thing that I think makes a difference with the amount of debris, but have no specific proof, is if you shoot a lot of burst mode either in continuous low or high. It seems to get the camera spewing a good bit.
Personally, I would rather not spend a lot of time going through cleaning every couple of hundred shots, but heck, if you have the time and desire, go for it. One thing is very clear with the D600, owners who keep it are going to get highly proficient with cleaning sensors. I wonder if Nikon has stock in Visible Dust or Copper Hill.
I gave up and just went with a D800. I figured between the cost of repetitive cleanings, and no idea when or if Nikon was going to fix the problem, it made sense to me. I like taking photographs. I want reliability. I like the picture quality of the D600 just as much or more than the D800. The low light pictures in particular were terrific.
In the end, only you can decide what you want. For my part, I had no faith that in the middle of some great shots I was going to have to factor in unwanted spots. The amount of dust from the D600 is more than most cameras spew. That is the bottom line. Good luck with your decision, and yes, there is a great amount of information on the Nikonian's website.