Tried my luck at chain fishing today, and I managed to get my first shiny from it, and also my first Kalos shiny, Clawitzer. It was a female with the perfect ability for it, Modest (no synch!), and the nature Mega Launcher.
Still adapting to X/Y's radar, but I'm sure I'll improve in the future. Just like D/P/Pt, the more you use the radar, the better you'll be using it successfully.
EDIT: Just got myself a Shiny Lampent in a Friend Safari while looking for the third pokemon, but unfortunately, he didn't have the hidden ability, Shadow Tag.
He's got a Naughty nature as well.