"Falling into the mini-DSLR category of mirrorless models, the Panasonic G6 in many ways matches and even betters similarly priced DSLRs. Indeed we can't think of any DSLR or CSC model that offers all of the G6's features, which happily are matched by great performance, proven handling and seemingly endless customisablity.
Image quality is really the only obvious achilles heel of the G6 when comparing it
to a bigger sensor camera. Although delivering excellent quality for its Micro Four Thirds class, with noise not rearing its ugly head until ISO 1600, and offering accurate colours and good dynamic range, it can't quite match DSLRs or the APS-C sensor compact system cameras at higher ISO speeds."
No longer the stuff of rumors, here's the E-M5 straight from the horse's mouth:
Not only is the GH3 physically the largest and heaviest micro four thirds camera to date, it is so big it actually towers over some aps-c DSLRs, like the recently introduced Sony SLT A37. But Panasonic did not blow up the size just for the looks. Behind the (large) hood, there's a substantial amount of new goodies and refinements, needed to keep up with the current competition crowd in the top mirrorless segment. . . . read more
Before we go on to the main dish, here's a reader commentary on the same Engadget page:
"Why does everyone simply forget panasonic G3? It has the same sensor as GX1, marginally bigger body but with EVF builtin, an extremely handy tilted screen with touch focus and same resolution as gx1. It's basically the same or even better than GX1!!