There is one point these full frame advocates always neglect to point out, either because they simply don't know it, or don't understand it for that matter The point is that the m4/3 design allows for a more "straight-on" path of light thru the lens and onto the sensor, whereas in full frame, and even APS-C for that matter, there is a somewhat angled path of light to the sensor at the edges of the frame. It is basically because of the physical design of the m4/3s lenses relative to the sensor size. This net effect is that the m4/3s system can render relatively sharper images at the edges given common lenses, whereas in the full frame or APS-C realm, you would need to get optimum glass to achieve the same effect.
If anyone is interested, this was discussed on a recent TWIP podcast where Gordon Liang was a guest. I'm going to try and look it up and post it here, because I think it's not common knowledge, and his explanation was technically sound. A lot better than I can explain it, for sure.
This guy's argument is a tiresome one. His points on depth of field are valid, but as for resolution, it is hogwash. Resolution has nothing to do with image quality (eg. sharpness), and only serves to allow for better cropping or magnification of images.
He's definitely biased, and is basically waging a loosing battle. It's only a matter of time before mirrorless systems begin to outsell mirrored DSLRs. Just look at the current fiscal results for Canon and Nikon.