Saw it yesterday and it's safe to say it exceeded expectations. Urban *was* Dredd, no question. He had the tone, attitude and dry humour down pat. Thirlby did a great job and made the role of Anderson her own. Headey was surprisingly understated, yet intensely psychotic as MaMa. Not an easy thing to do without going OTT.
It's a shame it's not doing well at the box office, but not surprising. I think this is one that'll thrive on DVD/BluRay, so it may make it's money back at least. Let's just remember a few other films that tanked at the box office: Blade Runner, Citizen Kane, The Shawshank Redemption, The Princess Bride, 12 Angry Men, Children of Men, John Carpenter's The Thing and Fight Club
to name but a few.
...just saying. The box office take is by no means a reliable indicator of success.