Originally posted by eddie1960 thing is the GH2 will elicit the same sort of response as a kr because it still looks like a bigger slr
one thing not mentioned is also the difference in DOF. if you want nice OOF areas and good portrait performance you will be better served by the larger sensor Pentax
to get the same effect as a cheap fast 50 f1.7 on apsc a m4/3 camera would need a 35 f1.0 not a lens that even exists and if it did would negate any size benefit to m4/3 as it would be huge (have a look at the noctilux lenses)
In my experience, a photographer's intent appears to be inferred by two things - the size of the camera/lens and whether or not the camera/lens is brought up to the photographer's eye. Someone with a Pentax K10d with the DA*60-250 is going to draw a lot more attention than the GH2 with the 20mm F1.7. Likewise, the K-r with the DA40 pancake will probably draw less attention than the GH2 with the 14-140 zoom, particularly at the long end.
But the GH2 with the 20mm F1.7 held at arm's length, and composed and shot with the flip/twist LCD draws less attention than if the same camera/lens is brought up to eye level, and less attention than the K-r with DA40 brought up to eye level
So even if you assume that the GH2 and K-r are more or less the same size, the rear LCD of the GH2 makes it even more stealth. Yes, the K-r has Live View, but if is as noisy as the Live View of the K-x, then it's not very stealth. We also can't forget that we are comparing the extreme ends of the two formats - the largest M43 vs. the smallest (or close to the smallest) APS-C Pentax. If you can live without a viewfinder, the GF2 has no peer in the Pentax world.
Finally, regarding DOF - the 20 F1.7 has pleasing DOF wide open and is still sharp. And while there isn't a 35 F1.0, there is a 25 F0.95 Nokton which is a bokeh monster.