Followed your link, it's from 2008, that's 5 yrs ago
secondly on my Mac retina it was immediately apparent which file was which. The Canon file is quite dead and lacks significant detail in the leaves... even on a 13" monitor (albeit a good one!)
so a lot has happened since 2008, a lot of new sensors are coming out, monitors are better, lenses are getting better. In summary both ends of the spectrum are improving and there are new designs that will make large format even more narrowly focused (pun intended)
Guarantee that an RX-1 or Sigma DP will blow both those cameras away on IQ... as will several C's, S's or N's
Yes the article was written years ago but I remain to be convinced that the situation has changed. In fact I think if anything the gap between smaller than "FF" and FF systems is harder to detect.
My own tests showed that my G1 when fitted with a nice lens produces images that can be lost amongst 5D images with no one being able to tell them apart on screen or in print (A3) better than chance. The G1 images need to be cared for and coaxed a little more but they get there and I fully expect newer CSC to have if anything closed the gap a little to more modern full frame cameras.
However, I can only speak for myself and the people who couldn't tell G1 images from 5D images.
I'm happy with the performance of my quite old G1 at low to middle ISO settings, the only issues that bother me are the light output from the EVF and its limited dynamic range and being forced to use ND's more than I do with my DSLR. If these two issues (EVF and ND's) could be fixed I wouldn't pick up a DSLR again.