Batman Arkham City Update

I did finish off the Harley Quinn DLC.  It didn't take too much to finish it off.

So I've been running around the city trying to find all the riddles.  I need 400 in order to unlock The Joker.  My biggest problem was that no ? were showing on my map.  So I've been using this guide from over at Games Radar.  You can bring up each section of the city and below that picture, they show another picture of The Riddlers riddles.  They matched them up by numbers so you can compare to yours to see what you're missing, then look on the map to see where it is on the map.  It is helping me find tons of riddles I've missed.  I've cleared out most of the city and realized I didn't have hardly any in the Museum.  So I almost got done with it last night but I couldn't figure out how to get into the back room from the front side.  I might have to leave, go out and around to the back of the building and come in that way if I can't figure it out tonight.

Once I have those, I'll be with in 10 of having the 400 I need.  Actually, just realized, I have to go get Catwoman and go back into the Museum to get 2 or 3 tropies setting in there for her as well so it'll cut my numbers down some.

After that, I'm still missing quite a few in the Steel Factory.  So I'll go there to finish up getting to 400 riddles.  I'll be glad too as the one screen that I don't have hardly any on is where you have to perform actions in order to get the riddles.  Some are probably doable but I just don't want to have to deal with that.  I'd rather just run around and find riddles.

Once I finish that up, the debate is on for where I want to beat it on New Game + and go for Perfect Knight Day 2 or just be done with the game.  I'm trying to finish up games before the Xbox One comes out and this would let me be done with this game.  I might try some of the fights to see if I can't earn a few of the combat ones but that would be all I would do.  Guess I could go for all the catwoman riddles as well just to add a small 10 point achievement.  I will at least go over 1K with all the achievements I will have gotten.

Would you go for finishing the game all over again or just let it be and move on?