Decorators vs. classes in python web development

I've noticed three main ways Python web frameworks deal request handing: decorators, controller classes with methods for individual requests, and request classes with methods for GET/POST.

I'm curious about the virtues of these three approaches. Are there major advantages or disadvantages to any of these approaches? To fix ideas, here are three examples.

Bottle uses decorators:

@route('/')
def index():
    return 'Hello World!'

Pylons uses controller classes:

class HelloController(BaseController):
    def index(self):
        return 'Hello World'

Tornado uses request handler classes with methods for types:

 class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")

Which style is the best practice?