I have good luck with v bands, when mocking up you always must tighten the all the way down each time. I tout I could get away with out it once and it came back to bite me. The vibrant assemblies come with a fine pitch T bolt and some sort of soft metal nut, they work great when it's all done but they do not like to come on and off all the time while I'm mocking things up. To get around this I just bought some regular long hardware store bolts and put those in. I also carry a spare t bolt and nut in my glove box, but that's me being over prepared.
The biggest difference I have seen between different v band brands is how much room they take up. If you have a pipe and want to add a vibrant v band assembly it's going to add 1 inch to the over all length. I had another cheaper brand and it was closer to 2 inches which was a real pain and ive never bought one of those again. I plan to try out using a double slip fit since the lower over profile makes it easier to fit with out worrying about hitting the ground or something.