Only bad part is if you want to get great it can take a long time especially if you play with harder classes like demo-man soldier spy or sometimes sniper. That is the only bad thing i can think of.
So definitely download load it.
It is free unless you buy items in game.
So if you saw the animated characters and decided not to get it well its free so download it and i guarantee you will fall in love with the game.
The game play is amazing, but the dialogue and voices of the characters make every second perfect. The game can be fun even if your team gets demolished.