"... it's very difficult to jockey the camera into position for a vertical shot."
It is for carrying not shooting as this thread is. The Black Rapid has a quick realease clip and you really need to remove the camera/lens unless it is a quick snap shot. And the tripod collar can be kept loose if you need to do vertical.
Never, never carry a big lens with the strap attached to the camera, any strap. 
@jay968 wrote:
I have read conflicting opinions on whether or not it is ok to carry a 70-200 f2.8 ISII on a 6D or a 5D MKIII using the standard camera strap instead of supporting the lens first. Will this cause undo stress on the lens mount with either or both of these cameras? Does anyone know what canon recommends?
I've been carrying 70-200s and similar size/weight lenses that way for many, many years, without even a hint of a problem. The bayonet mounts on the camera and lens are quite strong. I'm often shooting with two cameras, so one is hanging at my side while I'm working with the other. My most frequently used lenses include 70-200/2.8 and 300/4 that are close in size and weight, and one or the other is practically always on one of my cameras. Other lenses are 70-200/4 which is a little lighter, 24-70/2.8 and, smallest, 10-22mm (about the same as 17-40 on 5DII).
Really big, heavy lenses, such as my 300/2.8 and 500/4, have straps of their own that I use in conjunction with the camera strap.... when those lenses aren't on a tripod or monopod (and even then I often wind the strap around the 'pod as a bit of extra security). Those lenses have built in strap rings, so I'd say Canon "recommends" a bit more care and extra support with them.
Sorry Canon, but I don't use the OEM straps provided with the cameras. I replace them with Op/Tech, much like the ones Canon Professional Services provided at times. Those are much kinder to my shoulders and back!
***********
Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM
