Not interested enough to check it's base stats =/
Friend Safari let's you can pokemon like any other Safari. but this time the pokemon you get in the safari is dependent on your friend. And you can capture pokemon normally not in the game as well. Every friend has a certain type and when you pick someone, you will only get pokemon from that type.
Also, each friend gives you a max of 3 pokemon.
As an example, if I pick you for Friend Safari, I can find the following pokemon: I get Rock type and I can catch Nosepass and Pupitar. Only 2. But there's on more spot free so if you beat the League another pokemon will appear in your Safari.
Gwee gives me: Ghost type, Lampent, the ghost grass tree thingy, Dusclops
So..the more friends you have registered, the more different pokes you will be able to catch.