I don't know much about the comic version of Robocop or Dredd, so i'll back Robo movie feats
Cons for robo
-Once he's locked on, he doesn't miss unless his radars damaged
-His body makes him a walking tank, only high caliber can pierce him
-He can fly with his booster wings
-Pretty strong
Cons
-Murphy's pretty slow
-Damaging his radar forces him to remove his helmet, precious seconds he can't waste
Dredd's armour piercing rounds would punch through Robocop no problem I reckon. Hi-ex would likely ruin Murphy's day too. The tech level is so much higher in the Dredd-verse, just not remotely comparable.
Obviously Robocop could also kill Dredd with a few well-placed shots, but I'd back the guy with genuine comic A-list skill to land a critical hit first more often than not. It's not like he doesn't have decades of experience fighting against high-end cyborgs and robots etc.
Cheers.