The Olympus OM-D E-M5 was my first mirrorless. It is a micro 4/3 camera. One thing I love about micro 4/3 is that all the components are compatible with everything made for micro 4/3 whatever the manufacturer. So my Panasonic lenses work on my Olympus body and vice versa. The internal 5-axis stabilization of this camera is it's strongest point. I was able to handheld some one second shots.
A very small camera with the same sensor as the E-M5. It's my wife's camera. The picture quality is very good but you sacrifice the ergonomics for size.
I love my Panasonic GX7. It fits right in my hand. The ergonomics and customization of this camera is awesome. The video is also better than the E-M5. It is a bit lighter too and has a better screen and viewfinder (tilt-able). The internal stabilization is not as good as the E-M5 and it is not weatherproof. It is my go-to camera.
My most recent body bought in july 2014. Sharing the same customization and with even better ergonomics than the GX7. This camera is a beast in video: shooting 4k and variable frame rate up to 96 fps in Full HD. It has better dynamic range than the 5D Mark III at base ISO. But it is still light and quick.