Quoted from rad:Get both and ditch the DM. Both JD and JP are great games - much better than DM.
this is what i'd go with if it's an option. if not, dredd all the way. JD is one of my all time favorite games; love the theme, love juggling the ball with the flipper, and the flow. my god, the flow. DM plays very different from JD so i wouldn't worry about that. almost picked up a JD, but went with a fixer up TZ for a little more.