Panasonic 14-42x on the E-M5: no problem
When the Panasonic PZ 14-42x came out, there were reports of blurry images at certain shutter speeds, the shutter speed apparently interacting with OIS. I used this lens with the GX1, and never found the problem to be as great as some people reported, but it was there when I looked for it. Now that I have the E-M5, whose IBIS bypasses the OIS of the 14-42x, I wanted to see if the problem was still present. The shutter speed that had been particularly problematic with the GX1 was 1/160, so, as a practical test, I did some shooting (at Allan Gardens in Toronto) with the E-M5 set at shutter priority, 1/160, Auto ISO.
The result of this admittedly limited and informal test was that there was no blurring that I could detect. The photos below are at 14mm (first two), 34mm (third) and 42mm (fourth). BTW, the fourth photo was at ISO3200. If I had not maintained the self-imposed shutter speed of 1/160, I would have changed the shutter speed to 1/80 or even 1/40, which would have resulted in correspondingly lower ISO.