I´ve being using my GH4 for months now, mostly with my Panny 25mm F1.4, SLR Magic 12mm F1.6 and Panny 45mm F2.8 Macro.
Specially with my 25mm F1.4, I get really nice DOF and nice bokeh, beautiful rendering.
I work as a 3D artist and have decent skills with Adobe Software, grading is a pleasure with the in-camera footage, even being 4:2:0 internally.
Of course, for me raw would be fantastic, but I´m more than happy with my camera. I´ve already owned a 5D MKII and a Nikon D600, but the size, ergonomics and true hybrid performance is simply great in my opinion, I had the chance to use the camera both for print and video work, both professionally.
And even better, I use to do some 360 pano pictures and now GH4 has support to promote control (a multi exposure, timelapse and other goodies device). With a 8mm fisheye, I can get a full 360x180 panoramic bracketed picture (HDR).
All of this in one single marvelous camera.