The D600 fits somewhere in-between the D700 and D800, with neither of the two new cameras taking completely over the D700's crown. It's a handsome camera, with the broad chamfer seen on the D4 and D800. Handling is like a cross between a D800 and the DX-format D7000, and little has been compromised in terms of usability. Twin control dials remain, as does a top LCD plate, lockable mode and drive dials.
The D600 adds twin SD card slots which you can run as backup, overflow, or as separate raw and JPEG saves. The backup feature will be a big draw for critical shoots where losing data would be a disaster.
Battery life is rated for a long 900 shots; there is an optional battery pack, but unlike on the D700, the MB-D14 will not increase the D600's 5.5 frames per second shooting speed. The D600 also has a Quiet drive, which is quieter than the normal drive modes but isn't exactly whisper quiet. The Canon 5D Mark III's silent mode is still quieter than the Nikons'.
Full-frame shooters might miss the round-shaped eyepiece, but the viewfinder is still as large as those found on full-frame cameras (DX upgraders will be in for a treat). Most might find the rear d-pad smaller and fiddlier than they're used to. And they will want to treat the D600 a little more kindly – while the camera is dust and weather sealed, only the top and rear body covers are made from magnesium; the rest is made of plastic. Even then, the camera feels dense and solid in the hands.
The D600 is missing a dedicated AF On button; AE and AF lock are combined onto a single button. The ISO button is the last button beside the rear LCD monitor, unlike on the D800 where it's on the top plate. But since it's the last button, it's much easier to find compared to the D7000 which had it as the second-to-last button. In the dark, you can hit the Info button to the right of the monitor to launch an information display, which acts as a secondary screen, and you can change settings like ISO when you press the relevant buttons.
At 760g, the D600 is the most compact and lightweight full-frame DSLR Nikon has made. It's certainly lighter than either the D800 or the D700, but it's still a full-frame DSLR – make no mistake, you'll feel it when you hold the camera for an extended period of time.