Rode into Bath today and was chatting to a bloke on a very shiny Salsa Marrakesh (roughly Salsa's equivalent of a Long Haul Trucker) with bar end shifters. He said they are fiddly to use – 10-speed so the increments of lever movement are very small – but pointed out a benefit I'd never have suspected; they encourage you to use the drops more, not just when slogging into a headwind or barrelling down a hill, but in situations when you might want to change gear frequently. So in traffic, for instance, you'll be using the drops; in fact the drops become your main position, and this "helps make the bike more stable."