I would go with Pete's serve.
The ball is in Pete's hands, he can do what he wants with it.
Federer's forehand is contingent on so many things, how fast the ball is coming at him, how much spin the ball has as it comes at him, where he is positioned on the court at the time of impact and where his opponent is positioned.
But with the serve, it's your call each and every time.
That is all.