Simply a fun and immersing game
The online play is just what you would expect from Halo, however experience and ranks play a huge role in how you level-up, and who you play with. The online maps are extremely fun and various and the new map pack includes some very engaging new areas. There are so many combination of game types and maps available that it is sure to please anyone and everyone. At the end, online play is the reason to buy, beat, and keep playing this game.
The only negative about this game is the graphics. The game is beautiful, but I find it not as sharp or up to par with what a next-gen game, especially Halo, should look like. However, this little complaint does not and should not deter you away from this game. Buy it, and have fun.