its an excellent game, and has a huge amount of players on at any time.
but be prepared for a steep learning curve. this is not the type of game that u can just pick up and play. it will take time to get used to the controls and gameplay. be prepared to be cannon fodder for the first few weeks of playing. but stick at it and u will really enjoy it.
there is a new update that is released very soon, that will include offline tutorials. so that should make it a little easier to get to grips with it.
there seems to be quite a shortage on the disk version of this game. but can be downloaded on the playstation store.