At the risk of drawing fire, I prefer the feel of barcons, in fricton or indexed modes to anything else, but being able to brake and downshift simutaneously for a tight turn or stop is a big advantage of STI/Ergo levers. Otherwise, friction is easier and cheaper to set up and maintain, and gives me more of a feeling of control being able to trim out any gear. Don't have to fine tune the derailleur settings as often, either. I don't believe either is faster enough to make a difference if the bike is set up properly.