I'm not in the slightest bit worried about the D600 and have already ordered mine from Berger-Bros.com.
The D600 is nothing more than a Nikon D7000 with a slightly reshaped body, 24 MP FX sensor, slightly modified multi-CAM AF module, and streaming HDMI video like the D800. The Nikon D7000 is a very stable camera with a proven operating system.
Nikon is all about maximizing profits right now, due to the massive losses incurred from the Japan earthquake and Thailand floods. Why reinvent the wheel when you can take 90% of the tech from a proven camera (D7000) and re-purpose it for the D600. I feel quite safe in early ordering.
Honestly, I may just be fortunate, but I have never yet had a bad Nikon, even though I literally get some of the first that come into the USA. My Nikon D2X was one of the first 1300. My D300, D300S, and D800 were one of the first 1500 in the USA. I have to get these cameras early for book writing purposes and take a chance, I suppose. I've not yet been burned yet.
There's always a first time, but my order is in, and I will be taking delivery next week in order to start writing Mastering the Nikon D600. If I find any weird things, I will report back in here.
============================================== Darrell Young (DigitalDarrell) www.pictureandpen.com "Better too many words than not enough understanding." ==============================================