Just a short post. I just got a Panasonic DMW-MA1 4/3 to m4/3 adapter as I recently sold my Olympus one with a camera and lens I sold as a kit.
I tried it on my PanLeica 14-150mm zoom on the GH2 and I'm sure the AF is faster. I can't compare the two side by side anymore but the lens definitely seems quicker to achieve focus. I'd assumed the two adapters were pretty much the same, maybe they're not.