Having said all about affordability, I would still consider GH3 higher over any FF with its primes or new f/2.8 (FF f/5.6) lenses as the IQ at lower resolution should be similar (if not same, your milaege may vary) and higher ISO over 1600 to 3200 with some marginal difference and above 6400, well I don't care as I never used such insane ISO in last 12 years.
As affordability also boils down what size and weight you can carry and been an enthusiast traveller, it matters a lot to me, with shrinking FF/APSC camera bodies, their lenses are still quite big and heavy.
Probably the most critical factor here is DOF as it will be same on all ISO settings and no advancement in technlogy can match these two formats on these grounds. Except maybe some IB software PP in future. But it again depends on your shooting style, I prefer DOF of m43 in most of the scenerios I deal with, f2.8 on m43 is more useful for me than f2.8 on FF; probably a wedding photographer could have a different level of acceptance!