Having struggled with the problems of walking with an SLR and heavy lens combined with carrying binoculars, I have tried a wide variety of straps, with varied success. My purchase of the Op/Tech Utility strap system was more in hope of a solution.
Initially too I was unsure about the safety of only attaching the camera by one corner - and having always in the past carried cameras on my right shoulder to sit on my left side, I was worried about the Op/Tech's requirement that the camera must sit on the left shoulder.
However, first outing and I was a convert. Carrying the Canon 7D with the 400m L lens, quite a weighty combo, I felt the weight far less than with my previous Op/Tech or Crumpler straps. The way the camera hangs on the right side means that the side grip is ready to hand - and when lifted, the camera slides quickly and smoothly up the strap to the eye - real quick-draw! I don't use a lens cap, only a lens hood, and so am always ready for the snap-shot.
Some posters have complained that it is difficult to use the camera in portrait mode. I have had to modify my technique a little, so that my controlling right hand (on the camera grip) is on the bottom of the camera when shooting in portrait - but I've adapted easily to this.
By the way, there have been some posts suggesting that left-eyed used might find the system a problem. I am left eyed, and have found no issues at all with the Canon 7D and the Canon 60D.
SO - for me, a brilliant solution, and unhesitating 5 stars.