I just say it's a game with TF2 classes, Mirror's Edge parkour, Borderland's weapons and a pinch of badass thrown into the mix!
Don't forget the story!
No offense but it sounds like you are manipulating your friends. Why not show them videos and let them make their own conclusions about the game?
They're my friends. I know what they like in a game, what they want in a game, and what (like myself) will make them more likely to want to play Brink over TF2
in addition to linking them videos, forums, the wiki, and the official site with the dev blog of course. If trying to convince someone of something in an entirely open and friendly manner is manipulation then there's something wrong with this picture.