Many of the bands that gave birth to bluegrass sound a lot like yokels to modern ears. As much as the Carter Family is venerated, as they should be, they don't sound polished. Bill Monroe, the man who invented bluegrass, doesn't either. Still, while it may seem incongruous, the Carters, Monroe and all of the people that we think informed the music when it was nascent used it as an expression of class and pride, and they projected professionalism in their music that many simply didn't have in life.
Those traditions die hard, and there are still many bluegrass bands that don the suits, Stetsons and the stiffness that, they believe, suggests poise.
And then there are bands like Cadillac Sky, Old Crow Medicine Show, and Greensky Bluegrass that, quite literally, kick out the jams. They have the instruments, and they know the tradition that informs bluegrass as a genre, but they are young and have a lot of other influences as well. The result is a band that takes as much from the Grateful Dead and Railroad Earth as they do anyone else, and who get praise for the best reason of all: these guys are fun.
No suits or Stetsons anywhere.
See them live if you can. If not, have a listen here. They are a real treat. And they're from Kalamazoo, Mich.