Not sure he's finished, but I'm surprised he couldn't raise his game today. Tsonga looks like a cross between Muhammad Ali and Chris Kamara. Good player though, kept his nerve when it mattered.
Still a very good player, and still capable of great performances, but Tennis is a young mans game and at 29 he is well past his sell by date. Such was his dominance in his prime that even when his performance has dropped as he's aged he has still been able to win grand slams in his late 20s. In all honesty he has been past his peak for a while now, even in the 08 final loss to Nadal he was past his best. Federer in his prime was unplayable on grass and hard courts, and only Nadal was his superior on clay. But as far as overall ability goes Federer is the best player I've ever seen, the guy had no weaknesses, he was the complete player, so it's ashame to see him going out in the quarters, but no one can go on forever