Unfortunately (why only 3 points) has a concept-related disadvantage. The eyecups can be easily attached to the camera and snapped a little. What it comes easily, but also decreases slightly. I have in this respect to have some losses complain. The small hook snap unfortunately not so tight that the eye cup is firmly fixed. When take out or tuck into a tight photo bag to the eye cup dissolves quickly unnoticed - and it is already gone.
It would be hoped that Canon nachbessert here and the clip fit interpret something "tighter".
But well, that there is Amazon. Available and delivered quickly.