One of the most exciting features is the live updating of long exposures. This is a huge feature for those of us who do lots of low-light photography.
Previous Olympus MFT cameras have had (edit: single-shot) AF as fast as any DSLR, so I'm not too worried about that. It appears to work with 4fps as well, although it remains to be seen how well it works with moving subjects.
Also, they have a new 5-axis IBIS which I believe is a first.
I wasn't excited about the camera until I saw just how feature-complete the camera is. It really makes the MFT system complete and mature, now that they have a more-or-less thorough prime lens selection, with a few remaining ones coming out later this year.
you may be more interested in fuji x-pro1, which will have much better IQ than e-m5 (and optical viewfinder).
How are you making such conclusions on two cameras which are yet to be released, and even thoroughly tested?