Free to play and Free to Win, Cross Platform and Active Dev team that is fixing the issues that are popping up (like server issues). These points alone I feel are enough to say you should at least try the game and see how it feels.
But more than just that, the usage of portals truly changes the game when it comes to the speed and the way we think of cover/ positioning in firefights. Camping becomes completely infeasible if your opponents know the basics of portals, shootouts are more dynamic when you can portal to behind your enemy or drop a portal and shoot them from a different angle.
Overall its already a great game, and its only going to get better with time.