I did quite a bit of research on this lens and competitors lenses in this price range, The Tamron 150-600 is very popular, and I can certainly see why. I consider myself to be an enthusiast level photographer.
This is a very good quality.lens., It is light weight for a 600mm telephoto, Auto focusing is fast, faster than I expected; This lens is very capable of producing sharp pictures; Great price for a lens with this kind of capability and quality.
This lens meets or exceeds my expectations; So I can't complain; No Cons!