Based on these videos I like the B-Grip more. I don't like my camera hanging with the Spider Holster, which in one of B-Grip videos subliminally addresses. But if I was using a telephoto lense then I'd get the Spider Holster.
For more info go to BGrip.com or SpiderHolster.com
B-Grip
For more info go to BGrip.com or SpiderHolster.com
B-Grip
Spider Holster