I just bought ODST the other day, so if someone wants to do any H3 matchmaking I'm game. And 4, since I have all the DLC for 4 as well.
I'm glad 343 finally added another ranking system to Halo 4 that's similar to 3s. Playlist-to-playlist ranks are nice. Oh, and if you play Flood and get in 2nd place 2 times in a row, your rank shoots up about 11 ranks if you started at 1.