Black Rapid RS-7 here as well. For photographing time consuming events like dogshows etc there is no competition. The one grip I have is, I'd like to see something similar for other tripods as what 3leggedthing.com developed. A quick release/tripod mountplate for the black rapid.
I was also looking at the SunSniper, which is a bit more secure, but it was so hard to get a hold of one I stopped trying.
Actually, that's my second gripe with the RS-7. The quick release lock at THE BACK. I used cable ties to really lock it. Sometimes you move in shady areas and it is just too easy for a quick fingered thief to unlock it and swipe your camera. Not often but sometimes.