This shield is mainly used by RDM and BST but has uses for WAR and PLD.
A good RDM will be equipping haste gear for stat-independent spells (haste, refresh etc) and this is nice addition to a recast set. Often combined with Seveneyes or Fourth Mace for Conserve MP.
This shield allows BST to reach 25% haste, as well as providing a nice little boost to STR, a very good shield in the right situation.
PLD and WAR would use for more fun as a PLD would normally use a Tanking shield.
WAR would normally use a GA whenever they are not subbing nin and probably dual welding when /nin.
But for a pure offensive PLD this would be a nice addition to a haste build.
I have no idea why SE put SAM on this, as SAM has no use for a 1 handed weapon in the modern game (Spirits Within spamming SAMs died a long time ago)
This is actually in incredibly amazing shield for PLD up until General's Shield (Due to the Enmity+ on Gen for exp situations) and exceeds most shield PLD can use while soloing early on due to the haste bonus =0
WAR, BST and RDM can make uses of it, i guess SAM too when messing around =P
Overall the 1% Haste makes it more viable than you'd expect =O! Definitely worth it to pick it up if you plan on leveling any of those jobs (RDM and WAR won't see a lot of "Exp party" as they generally either not melee or use 2 handed weapons or Dual wield)