Mesmerize (Mez) is the preferred form of crowd control Shards of Dalaya and the only one that effectively shuts down casters. Enchanters have access to the most effective mesmerize spells, though both Bards and Necromancers can be called upon to mez.
Mesmerize spells generate high amounts of aggro, and players may wish to use aggro reduction methods (such as Feign Death or Memory Blur spells) to reduce their chances at being attacked should their mez wear off or be broken. Mesmerize spells are broken by any attacks or damage, but cannot be broken pets which will not attack a mezzed target.
Enemies with high Magic Resist will not only resist mez more often, but have a chance of mitigating the mez, and breaking out before the full duration is over. For that reason use of the Tashan line of spell is recommended in conjunction with mesmerize spells.