I have three lenses in this range, the Canon 70-200 f4 IS, the Canon 70-300IS and this.The Canon non-L lens and Tamron are more or less identical for sharpness with a tiny victory for the Canon, although it's more expensive.

Very good value, lens barrel nice and wide for easy gripping, good stabilisation, although does jar in the viewfinder when it comes on, fairly sharp at 70-200mm; Good warranty

Average to poor sharpness between 200-300mm, turns the opposite way from Canon lenses; Makes an odd click/crunch on mounting; I wouldn't want to get it wet

I really took a long time to purchase this lens. It was a mixed feelings on going for a third party lens for my Nikon D3100. The reviews of this lens and that of Nikon helped me on concentrating mainly on the VC of Tamron against the VR of Nikon, the price of Nikon 70-300mm VR 4.5 -5.6 vs the price...

An absolute dream of a lens! Coupled to my Sony A77ii it is giving me the finest results I have ever had in over 60 years of photography, it is an amazing piece of equipment.

I was very excited to receive the lens but was very disappointed, really. I was going to shoot a football game and thought this will be a win. I did not take my canon len with me. Anything in the range of over 100 was not focused. I thought it was me. I tried it with tripod and the issue the same.

Tl;dr: low aberration is a boon, distortion is well controlled, Tamron priced it well The full review: Tamron made this lens to fit well in an area that is kind of empty: mid-range telephoto lenses under $1k, and the features that it offers is excellent.

The Tamron SP designation is reserved for lenses developed with special emphasis on extraordinary photographic performance. Engineers are free to innovate in an uncommon atmosphere where optical performance comes before price, resulting in lenses that satisfy the demands of discerning photographers.