Thank you, clixpix. The Tamron 150-600mm and the Canon 100-400mm II + the 1.4x extender are about equal in resolution. Both are very sharp. I like them equally. Both have slightly different advantages. The Canon 100-400 + 1.4 extender is smaller and slightly lighter and can focus between a minimum of 2-3 feet. This has very fast auto focus even with the 1.4 extender. Without the extender the auto focus is extremely fast. The stability is about the best I have used. The special and costly lens coatings produce a sharp contrasted photo. When using the 1.4x III extender. you can only use the center focus point and you lose one f/stop which is not a big deal. The price of this lens and extender will be about $1500 more than the Tamron 150-600mm lens.
The Tamron is very sharp and fast at auto focusing and has good stability control and you can use all your focus points with evaluative metering. It's slightly longer and heavier than the Canon lens but almost the same weight as the Canon with the attached 1.4x extender. It's closest focus is about 8-9 feet and will give you a sharp close-up photo. I really can't tell the difference in IQ between the two. I think the Canon combo might have a slight edge in sharpness of 1 or 2% which is not worth mentioning. The Canon 100-400 II is more rugged and weather resistant and has more controls and more expensive. If you want a great 150-600mm lens for your money, the Tamron will fit your needs and if you use a Canon 7D Mk2 with it's 1.6x factor, now you have a 960mm lens and won't need an extender. If you want a smaller, rugged and slightly lighter lens for more control, then the Canon 100-400mm lens will fit your needs.
As I said before, I like both equally. It all depends on where and what I may be shooting and the weather, what lens I may use that day.