I am in a similar position, trying to decide on whether to buy a new body. My thoughts and priorities may be a bit different than yours, but why do you assume you need FX for wide angle? The Nikon 10-24DX or 12-24DX will give you almost the same angle of view on the D7100 as the 16-35FX will on a D600 (the 10-24DX will be wider). The DX combination is also cheaper, lighter and benefits from a better AF system with the AF points spread much wider across the frame than the D600. If you 'loved' the D300, then the D7100 seems to be an upgrade in most areas, and you can always enjoy the anticipation of a D400 later this year For me, a priority is the weight and bulk of the kit, and that is pushing me towards the D7100 at the moment, although I haven't pulled the trigger on the purchase.