It started with a threat on the Lens forum, but the development made me create a new threat in the Cameras.
I was not happy with the IQ on my 60D with some of the lenses. Just not sharp enough. I even sold the Sigma 17-70 OS recently in favor of the 15-85 lens, which helped a little. But I have a real problem with the Tamron 70-300 VC. At above 200mm, if I cropped a lot, e.g., for the birds, it was simply unusable. I sent this lens back to Tamron for calibration twice, and both times it came back practically the same.
Then I posted a request for suggestions on the Len forum, and somebody suggested to check the Tamron on another camera. I did, on the wife's T2i. What a difference! It was sharp. I did controlled testing - the same settings on the cameras, controlled lighting, a tripod with a remote shutter release, AF and MF, direct and live view, three different lenses, etc.. The results are the same. Sharp on the T2i, blurry on the 60D.
Somebody on the Lens forum commented that he had never heard of a camera being a cause of bad IQ. I do not know if it really so. So I would like to hear the suggestions as to what can be done before I sent the 60D back to Canon for servicing.

Try re-setting everything. Third wrench menu.
