Despite what anyone here may say, only you can judge if it's worth it. It's easy for people to say 'report it' but they're not having to live in the same community as the muggers. If you think you'll come across them again, think how you'd feel if you saw them, and they knew you'd reported it. Do whatever will let you sleep at night, and let you visit the same area without fear.
I've been involved in a few scrapes with shoplifters in my shops, and after seeing how pitiful the 'system' is, and what the repercussions of attempting to use it can be, I'd think very carefully before reporting any of them in future. Out of dozens of incidents I've only been visited by precognition officers twice, and I've never needed to go to court as the defence usually pleaRAB guilty and accepts a slap on the wrist.
Whereas the results for us were a little worse: One of my workmates was hospitalised, another got head-butted in the face, my ex-girlfriend was told she was going to have her face 'cut' and had to run into the nearest building to get away, and since I'm a big lad, four of them surrounded me and my mate and brought a screwdriver to 'do' me with. I walked away and thankfully they didn't follow. In no instance did the Police do anything, and in my case they didn't even turn up.