Thom Hogan (from all people) got a defective Nikon D3x: "the original camera I received was sub-par in more than one way". His main complain were the noise levels. He got a replacement and this trigger him to even re-write his D3x review. It seems that other people experienced D3x problems as well (according to his post). If you have an issue with your D3x, I would like to hear from you. Send some examples as well.
The bottom line is that If you are the fortunate owner of a D3x, it is worth to compare your results with other D3x owners and make sure you did not get a lemon. Remember the price you paid for this monster? If there is interest, I can create a group on flickr where you can send your D3x photos for comparison/evaluation.
Update: if you want to submit your D3x pictures for discussion/comparison/evaluation you can use the NikonRumors group @ flick.