If you're daunted by the 24 second recast time, remember it's an irresistable spell and lasts for 7 ticks or 42 seconds.
so it's great for mezzing a single mob and keeping him mezzed.
The problem with the recast time is that you can't mezz 2 mobs quickly with it. You can do one then the second one has to wait for the recast timer. So two mezz spells are good.