Thinking of buying the 70 - 200 f2.8. It is big and heavy. It weighs about 1.5kg. Together with the camera, they weigh more than 2kg. I am not complaining about the weight. I use hand strap with the 24 - 70 f2.8 and it doesn't pose problem.
However, for 70 - 200 f2.8, seems like the Black Rapid type (and other brands)is the only choice, as the fastener screw of the lens collar is on the undernealth.
I used to own the Black Rapid but sold it after using once. Reason being :
1. I don't like the camera to hanging upside down
2. The screw fastener came off the camera base due to up and down movement unexpectedly. But was luckily that one of my hand was holding it firmly.
Trying to google aroung for alternative that lug the camera in an upwards position, and with one arm through the sling.
Any bros have experience with other straps / sling.