DVDdecrypter is still my go to software for that even if development for it ended a long time ago.
If it fails to decrypt it, which is rare but does happen, then you have anydvd, dvdfab and makemkv(but that one won't make a playable DVD, just an mkv with the movie which would be fine for pc but maybe not ps3, don't know what that one supports).
With that said, I don't know if it's even possible to make an iso with CSS protection and an official player(like in the ps3 or something like powerdvd for pc) should be able to decrypt it for playback.
So if you're having an issue with an iso you downloaded, the issue is likely something else.