Hi,
The difference is very small. There may be sample variations but MTF measurement has also a built in uncertainty. Looking at the MTF curves I would give the nod to the CFi, as it is (or may be) sharper off axis.
But, I may also have a feeling that some compromises may have been made on later generation V-series lenses. I "upgraded" my Sonnar 150/4 CB to CF, and the CF lens has much better "touch" but I feel I cannot reproduce the MTF of the older lens. The Planar 80 I have is a CFE and I may feel the older CF lenses may have a better build quality.
Best regards
Erik
Mechanically the Cfi is supposed to be better (srping, less internal reflections...) but which one is better optically ?
Looking at MTF, the Cfi looks better wide open while the Cf at f8 looks sharper in the center.