My experience is almost exactly that of AlanU.
I used the dual BR strap for years and years when they first came out. They were fine for what they were, but like AlanU said, sometimes the lens hood would hit the floor when kneeling.
Worse yet, when using a speedlight on camera, the flash would almost always scrape the floor and get scuffed, not to mention the precarious swinging when having a gripped body with heavy lenses like the 24-70 brick and 70-200 on either side with speedlights.
I recently switched to a dual spider pro system and used some Tamrac lens pouches and the spider monkeys and it has been working well for me. The camera system no longer touches the floor, although because the cameras are now on my hips instead of near my thigh, my body profile is now much wider so I have to get used to that still in terms of navigating crowds and spaces.
There is also the consideration of the appearance factor. With the dual strap, your shirt gets creased and pulled in all sorts of ways when you raise and lower each camera for hours on end. If you shoot weddings, when it is over, your shirt is mangled with sweat all over everything, including the straps which are on your body.
I also noted that with the weight of my rig, my shoulders would get red and sore at the specific parts where your shoulders are taking the weight after a 10-12 hour wedding. Since using the spider system, that no longer occurs and I feel better at the end of a day.
Mind you, the BR system is comfortable and I have nothing against it for short period of time, but it had some annoyances I mentioned that may or may not matter to you.