Planetside 1 was already something.
10 years ago you could play with 300 other people on persistent maps far bigger than other FPS of that time.
Now Planetside 2 offers to play up to 2000 players at the same time on the same map (instance). Something I have never seen elsewhere. Even in Eve online (not followed Eve for 2 years though).
Sure you need to be organized with so much people. And the game becomes really interesting when your outfit (guild) can align many people. And when you are organized.
For instance on Miller server (the biggest European server) our French outfit (French Connection) aligns more than 80 players during our Friday night ops. This is real thrill to be part of such massive group. Which is finally only 1/6 of all other Vanu players !
Editor Sony has chosen F2P to monetize the game. And sure they push to have you pay.
But seriously nothing is free in this world and many players choose to spend money as they would with any non F2P other game.
For curious people, here are our films (sorry, in French when we speak). http://frc.planetside.fr/index.php?static3/tv-french-connection