Tacking on my unsolicited two cents - I gave Origins a very, very fair go (added an easy 30 hours to my playtime and even completed some challenge paths for my sense of accomplishment), and while it does try to emulate the success of its prequels, ultimately it falls short of its predecessor.
Arkham City is a perfect balance of all the elements introduced during the series; it doesn't feel incomplete (although Asylum works great as an entry point) yet it's not an overbloated mess like Knight. Its story also feels more emotionally involved and the plethora of characters is incorporated well.