I would also like to clarify that Max def Xatu isn't really an anti-lead, you should almost never lead with it (unless scarf/U-Turn Mindgames) as most rockers Crustle/Rhydon/Golurk/Rampardos/Seismatoad (barring Giga drain), beat it one on one. The idea is to bait them for stealth rocks and switch in to reverse them, which requires a good deal of prediction rather than a simple taunt, as a Crustle can easily anticipate an obvious switch to Xatu and Knock off/Rock blast it to death, faster than it can fight back and roost off damage.
I typically use Xatu for more of a midgame mon for switching in on harmless hazard setters such as Ferroseed (gyro ball does like 27%) and Max def Sandslash (Knock off does around 40%).
I'm not saying Xatu is overrated or is terrible at blocking hazards, I'm simply saying I don't believe it to be a good "Anti lead" when there are mons that can taunt and take hits along with it. Plus it is a lot more difficult predicting when they will use stealth rock over Stone edge, then simply clicking taunt/lovely kiss.
Don't get me wrong though, Xatu is fun with the mind games and I use it on 80% of my teams ;)
Deej Dy wrote what I think about Xatu, I was been very brief before, sorry. Despite you have to be very good to predict, your opponent will be not never sure your hazard will throw back.