I saw it today and had a blast. I actually felt the 3D was worth it. It's a shame this movie is tanking. I was the only person in my theater.
One little quibble I have though, is that the plot of this film is almost exactly the plot of The Raid. They take different approaches to the same plot, though, so I didn't mind it so much. The Raid is a martial arts film, and this is a comic book action film.
Just to let you know, the creators of "Dredd" were working on their film prior to and concurrently with "The Raid," so it's just a coincidence. IMO, "The Raid" is highly overrated. "Dredd" is a far better film.