It has been a great lens for my needs, especially the convenience of travel when take-along is limited or when I know a shoot where changing lens will be a hassle. I am on my 3rd 18-400. First one rolled off a deck into a lake. The second lens was damaged beyond repair when an upset women slammed my camera into a counter top as she was racing past me in a gift shop in Alaska. I was not going to chase her down. Tamron said cost to repair was beyond their initial estimate so they offered a refurbished 18-400 for the same dollars as the estimate. The lens I received was brand new. My photographer daughter-in-law rarely takes her 18-400 off her camera.
I have a 7D II, tried the 18-400 at a camera store , it did not do very well. My Sigma 18-300 is a much better lens for me and does very good.............
My photo buddy uses the Tamron on his Canon 80 D. He has shot planes, trains and automobiles. I have the Tamron 16-300mm on my Nikon 7100. No problems with either. I do use back button focusing in Servo mode and Manual. Both are great tools in which you learn to use.
I have a 7D II, tried the 18-400 at a camera store , it did not do very well. My Sigma 18-300 is a much better lens for me and does very good.............
The Tamron is ok, but the Sigma is exceptional, and the only lens on my 7D II !!