I use one.
Dead weight against any team with a priority attack, useless unless it gets in at 100% for focus sash (which means that any sandstorm team automatically removes a turn of life from it), needs to rely on focus miss to destroy common pokemon (unless you feel like getting walled by just about anything), not high enough speed to outspeed stuff like Starmie, Gengar, Weavile etc., lack of Close Combat means you can easily predict a special set and not be too worried even if it is a physical set, can't use any item other than focus sash because it gets OHKO'ed by everything except offensively pathetic pokemon.
I use it because I really like Zoro and the ability is cool. Occasionally it does a really good job, this tends to be against teams lacking an answer to any decently fast special sweeper (ie. pretty bad teams) or in the late game where the turns are more vital and a single misprediction can decide the game.
I use him as his own ace in the sleeve and not to clear the way for another sweeper so I run Night Burst. I fake that it's a Gengar (getting experimentally switched for Mismagius) or a P-Z (which will get experimentally switched for P2) if Gengar is fainted, it doesn't matter what one as long as the outcome is the same: Zoro gets a NP without blowing the focus sash.
I think this pokemon would do a lot better in UU. Unfortunately, it's just too cool not to use and is thus unlikely to fall down there but it's also probably too strong for that tier. Otherwise it's a pokemon that rewards your skill in using it more than just DD'ing and then clicking Outrage.