How much closer are we talking, really?
On the E-M5 thread it actually looked like the 4.33" was sharper (In I think Doctor Mustard's duck phots?) than the 3.5"?
And when you say works fine - it works well? No difference in image quality between the 12-50mm port? And I thought the 12-50 port came with a 77mm-67mm ring?