So tf2 is free for download now -.-

Do these perks affect gameplay in any way? I might try out TF2 since there is so many people that say it's good (though I'm not a fan of FPS).

You only get 50 backpack slots, and since there are more then 50 unlockable weapons, you won't have enough space to have them all. Not that you need them all, some weapons have minor differences with the default weapon, and it will take a while till your backpack is full.

Otherwise, there's no differences, except for cosmetic items (you don't get hats randomly dropped).