Just a short post about the AF speed of different lenses in m4/3 system. As I stated earlier the current generation of Olympus M.ZUIKO lenses are blazingly fast to achieve the focus. The situation is not the same with Panasonic lenses, unfortunately. My Lumix G 20mm F1.7 ASPH lens has quite mediocre AF when used with Olympus OM-D body. Huge difference when compared to M.ZUIKOs and there is also quite much focus hunting too. The shot below was taken in reasonable indoor lighting (due my standards) with Lumix 20/1.7. M.ZUIKOs will focus instantaneously in those conditions having no hunting at all. Lumix 20/1.7 was instead hunting a lot. Not good. I am now thinking to get M.ZUIKO 17/1.8 lens to replace the Lumix. Many reviews report that the 17/1.8 has a really fast AF and has also more pleasing bokeh than 20/1.7.
My Sigma 30mm F2.8 EX DN is much faster in focusing than the Lumix 20/1.7. I think Sigma is very well acceptable even if not so fast than M.ZUIKOs. Also the focus hunting is very minimal with the Sigma. Very nice performance for so cheap lens!
All in all, some lenses are behavin', some are not.