A few years ago one winter a buddy and I were in the woods, taking photos of a wild bird. We were both in roughly the same spot. I had my K5 and 55-300 (lens bought new in June 2008) and he had his Canon 7D and Canon 70-300. Same lighting, F stop, ASA, etc. We clicked away at the bird and then compared pics. He mentioned that he felt my picture was sharper...in general better, in his estimation. He asked me why I thought that was the case, I indicated I did not know, as both cameras were top of the line and the lenses were both good consumer models.
Obviously this was not a scientific test, just a coupla guys taking a picture of a 'boid' in the woods. Who knows why my Pentax seemed to do better.. and I'm certainly no Alfred Eisenstadt, when it comes to aiming the lens and clicking the shutter.