How good Urban is can't be understated. The tough task any film trying to keep up the mystery of what Dredd looks like was always going to be that we know what the actor looks like. I'd have actually argued beforehand keeping the helmet glued to him was a bit pointless and not a deal breaker for my enjoyment of any future film.
But his performance here is good enough that, even though I know it's Urban playing him; even though I know what he looks like... I have no idea what the Judge Dredd of this film looks like under the helmet.