Tony
Welcome to the forum.
I have the Tamron. I think it is well worth the price but it does have its short comings. I had the opportunity to compare my lens to the Sigma 70-200mm f/2.8 EX DG OS HSM. From 70 to 200 my Tamron was sharper wide open. The Tamron becomes soft wide open between 200 to 300. While using the Tamron I tried to never go past 200. I have since replaced it with the Canon EF 70-200mm f/4 L IS USM. The Canon is much sharper and much faster auto focus than the Tamron. While shooting sports my keeper rate with the Tamron was maybe 50%. With the Canon maybe 90%.
The Canon you mention I have no experience with.
Another thing about the Tamron is the zoom ring rotated the opposite direction from Canon. This caused confusion for me at times when switching from one lens to another.
Based on reviews and experience I would probably go with the Canon EF 70-300mm f/4-5.6 IS USM

Look forward to seeing some images posted from you