IMHO two brothers is trash...
A lot of people think that but they are not any worse than any other can. It's just a fad coming and going. 5 years ago everyone thought they were the greatest exhaust ever. Nothing has changed since then.
But it is true that carbon fiber cans are susceptible to damage or loss on twins or big singles because of the huge pressure pulses. Not just TBR cans, all of them. When I had a KLR650, I heard many stories of the canisters falling off. But over on the GSXR forum, there isn't a single report of a carbon fiber canister falling off. They are currently out of style though. Lots of dorks repeating "Two Brothers is trash" after they hear someone else say it.
I personally like the looks of the Black Series and have one on my GSXR. With the P1X silencer tip, it's the quietest exhaust available, and unlike other silencer inserts, it still sounds good. I hate loud.