As planned I rented the 12-100 for Christmas Holiday. I made a mistake though in that I left the battery and charger at home rendering the camera useless. In the best Homer Simpson voice I can muster, "Doh!!!"
Christmas wasn't a loss for images as I had a second camera in my bag with two extra, fully charged batteries but I did not get to test the lens as planned.
So this AM I grabbed my first frames with the lens. I can't tell you much yet but I can tell you the range from 24-200 is amazing and it focuses fast on the EM1. Stabalization seems good too but it's different and doesn't lock the same as in body Stabalization. I can't quite put my finger on the difference as I have shot less than 20 frames with the lens but something is different and I can see/feel it in the EVF. It's good!
But I am excited to shoot it over the New Year and see what I think instead of just reading about it. First impressions are good though.