If you want the ultimate 70-200, it's the Canon, but you'll be spending a lot more for only a slight improvement over the Tamron. But nobody would blame you for being willing to pay for the ultimate 70-200, since it's the most popular portrait lens used by professional photographers. A lot of people are going to cry heresy when they see that I put the Tamron 24-70 a place above the Canon, but it's image stabilized, inexpensive, and the optical quality is very close.
IMPROVE PHOTOGRAPHY LLC IS A PARTICIPANT IN THE AMAZON SERVICES LLC ASSOCIATES PROGRAM, AN AFFILIATE ADVERTISING PROGRAM DESIGNED TO PROVIDE A MEANS FOR SITES TO EARN ADVERTISING FEES BY ADVERTISING AND LINKING TO AMAZON.COM. WE ALSO PARTICIPATE IN AFFILIATE PROGRAMS WITH BLUEHOST, CLCJ, SHAREASALE, AND OTHER SITES. WE ARE COMPENSATED FOR REFERRING TRAFFIC.