I thought the common consensus was that Green Arrow was the better archer while Hawkeye had the more ridiculous arrow arsenal and experience and other combat intangibles. I'd honestly probably give a very slight edge to Hawkeye overall.
Adding Mockingbird and Black Canary changes things up quite a bit. Mockingbird is a badass peak human martial artist and super operative but Black Canary is one of the best martial artists on DC Earth and has that sonic scream ability which should shift a close fight into Team DC's favor.