I kinda say go w/ the d600, just to save u some money, the v3x and the d600 r pretty much at the same rank. Unless u want the looks since u have the d500 (I have one too) and they look pretty much the same for the d600. It's your choice, the specs are pretty much the same, so go w/ the d600 or if u want something totally new, get the v3x. Besides how much can u get the v3x for?