I think the Berks sound great, probably not quite as loud as the Stillen/Berk combo.
I've got Nismo/Berk at the moment, and it's a little too mild for me. Sounds great when you get on it, but I don't want to have to drive my car fast all the time to get the enjoyment of the engine growl. On the other hand, I don't want something that is going to drone or attract too much negative attention. Hoping the Berks CBE will be the solution.
I don't want to give up my Berk HFC's they have definitely made the biggest difference in performance gains so far.