A mixture of the Emperor Hairpin with an Optical Hat. Probably the best piece for a Thief to macro in for use with Sneak Attack and/or Trick Attack coupled with a multi-hit weapon skill like Dancing Edge.
Just about all jobs that can use this can benefit in some shape or form from it. Of course some jobs get more use out of it and there may be no better piece for them but lets examine each job by known needs and uses
Monk: Dex/agi mods are nice for crit,acc,evasion though not contingent on neccessity. The accuracy and subtle blow are the key pts to look at for monk on this piece.
Thief: Every stat on this are great for thief. Dex/Agi mods for weaponskills, overdoing accuracy doesn't hurt. Ranged accuracy for bloody bolt and acid bolts comes in great hand. and subtle blow helps a bit for their flurry of dagger attacks.
Ranger: Agility for weaponskill mods. Accuracy helps for those that melee for tp since those -ranged accuracy rings don't help you much. Ranged Accuracy to help those sidewinder/slugshots. and hey subtle blow helps out too.
Samurai: I know there are better pieces but hey for the sams out there using a polearm and is the puller this helps you land that arrow mo