We rented this through Netflix, and finally had time to sit down and watch it last night. I was not expecting much, but was pleasantly surprised by this movie. It seemed very unusual to never see Urban's face throughout the movie, but in hindsight I actually like the choice, as it seems truer to the character as he is portrayed, which is to say no compromise. I think the choice not to humanize Dredd beyond what was shown makes sense in the context of the movie and his character. Another thing that I enjoyed was the restrained use of fx; there was obviously quite of bit of cgi, but it seemed to be used more in service of the setting (some of the external city shots were amazing), versus being used to substitute for action involving the actors. The stunt/action work seemed almost to be a throwback (in a good way), and I enjoyed this very much, having grown seriously fatigued of cgi-fest action pieces that have all the believability of another video game.
I give Urban a lot of credit for going along with the choice to keep his face covered, it certainly flies in the face (no pun intended) of typical actor vanity, and for me added to the credibility of the movie as a whole. It's nice to see creative choices that don't represent the typical route taken in Hollywood.