When did you last crush your consumer camera?
I have a D7000 - for the compact size and high for DX MP.
The build quality is quite good, but not as good as a D300.
Despite careful use my D7000 has a small paint wear mark I would not expect on a higher grade Nikon body.
I regard the D7000 as extremely good value at the price point, though obviously not top of the Nikon range.
The D600 should be similar relative to D4/800.
Many problems turn out to be a lack of intimate knowledge of complex modern camera equipment.