It seems to be best suited for taking on status inflicters/entry hazard inducers and stalling pokemon, however I see plenty of teams this gen that do not use those types of pokes. In addition, everyone is hard for aegislash right now, so that shadow sneak will drop it in one move.
--- I just wanna go home and have dinner with my wife.
Competitive-wise- No. It's incredibly overrated. Espeon can do nearly everything it does better. Morning Sun is a decent alternative to Roost when you aren't running Rain or Sand. Really the only reason for running Xatu is if you have a Rain or Sand team. And really, Magic Bounce is much more useful in the Sun.