With trout I use a leader if I'm running braid (PowerPro Yellow). For bass I really don't think it matters unless they are really heavily pressured. Bass are so aggressive I don't think they pay all that much attention to what they want to kill is attached. I could say the same for northern pike. Some fish are just too mean and aggressive for their own good. Now with that said the biggest trout I've ever personally seen caught in Montana were caught by a buy that runs straight braid, no leader. He consistently catches HUGE FRIGGEN rainbow trout between 25" to 30+" long. He's got a few of them on video like the lone below. All caught on straight braid. I can't wait to fish with this trout guru this summer. Just for the record Barry I go back and forth on the leader thing a lot myownself. There is that viable argument that one more knot is one more weak link between you and the fish.