OM-D + 12-60 SWD (with mmf-3) ... working or not?

Hi!

I already pre-own the fabulous Zuiko 12-60 SWD.

E-3 and E-5 are so big, that I would very much like to catch the tiny but in many ways more modern OM-D ... the kit lens for it, the 12-50, is problematic.

Are OM-D + 12-60 SWD pairing poorly together with the new mmf-3 adapter?

I have heard that the AF is not good, but... is it bearable? Is it good enough?

Thanks!