I am looking to dump my D7000 and am debating the GH3 and EM-5. One thing I can't seem to find, how is the focus tracking on the GH3? Better than the EM-5? I haven't decided if the video features are a selling point. Thinking of an EM-5, then adding a hacked GH2 if I need better video. But, if the tracking is substantially better, it could be a reason to spend the extra money. If not, the size, price, IBIS of the EM-5 wins.
All of these cameras are going to pale in comparison to a PDAF system on a normal DSLR. That being said, it's not that bad.
True, but the D7000's AF has been slow acquiring focus. Slow enough, that my E-PM1 would have had no issue in the same situation. Even shooting sports, I tend to pre-focus more than I track. So in all honesty, it's probably less of an issue than I think.
This video forum has alot more user information on the GH3: Panasonic GH Cameras GH3 owners are reporting much faster focus tracking performance as compared to the GH2 so that means it should also be considerably faster than the E-M5.
So far I've seen numerous reports of the GH3's focus tracking being the best on any mirrorless camera other than the Nikon 1 series, even over Sony's new PDAF system. So that seems like a plus. Since you are talking about video, it seems to work particularly well for that where critical focus is less of a problem. A few have compared focus to entry level DSLRs, which is certainly progress. I wonder if the "vivid" trick works on the GH3? Because using that and high framerate EVF I'm quite happy with focus tracking on my E-M5