Except Objective

Its optical qualities are known. It's close to perfection (color, contrast, sharpness).
Its big advantage compared to the behemoth that is the 70-200 2.8 IS II is its minimum focus of 0.90m associated with the opening F2. In other words, it lets you do the tight portrait, more "intimate" in the sense that it will reveal the best all the subtleties of a face always with the sweetness of the opening F2.
It is also much more manageable and discreet as a zoom, less versatile but easier to win (we did not say "arf it is too heavy I'll leave it").
Combined with a 85mm 1.8, it's a great combo for less than 2.8 is 70-200 II.
Some disadvantages anyway:
- No stabilization, which gives a small sensor on 200mm requiring high speed (but can more easily get through the large opening).
- This is a fixed focal length telephoto: sometimes we can not go back enough (hence the usefulness of a supplement 85mm).
- Sometimes we do not use it much, our desires / projects / needs do not require it. We then want to sell it. That's why it's not because he is excellent it is mandatory to buy it.