[Rover]

IMO the decision on FF vs APS-C depends on the type of photography that you most often take. If you most time use tele lenses then I would think a APS-C or DX camera suits you better since you can take the advantage of 1.5(or 1.6)x FL factor. If you most time shoot landscape with WA and UWA lenses then I think a FF camera is better. 

That, or a dedicated APS-C UWA. When Sigma 8-16 appeared, it voided the argument that there is no getting around FF for the ultra-wideangle shooting. In fact, tests here and at LensTip seem to indicate that it has better sharpness uniformity at the wide end than the 12-24 and doesn't have to be stopped down that much to get more of it.