I have never owned a Micro Four Thirds camera, but the Olympus Pen series have always come close to making me purchase one.
The best Pen was the Pen F and I had a good play with one a few years ago at a Photography show when it was first released. I was surprised and somewhat saddened to hear its now been discontinued.
It was a great little camera. Over priced but a good camera never the less.
With Panasonic adopting the L mount to go full frame, Sony pushing full frame and Nikon and Canon getting in on the full frame mirrorless scene, many feel that Micro Four Thirds is a dead end. I disagree and feel that it has a place, as does the cropped DX format and medium format. They all bring something to the party and have pros and cons.