I'd ditch the stand alone FBA for the RA FBA core and I would ditch Fusion for the GenesisGX core along Pico for 32X.
I like to use RA for where it makes sense, if there is a clear and obviously better option in a stand alone I will use it or when I have a preference over the RA core such as Mame.
Stand alone Mednafen for NES is not something I would recommend to anyone, even they say it's not the best out there. Mesen in RA or the stand alone version the best NES emulator followed closely by puNES, everything after that pales in comparison.