Previously something of an odd item, as the mace's quickness limits the damage potential, while its value as a caster item is dampened because the proc relies on melee combat. With the development of the tanking role of paladins, the mana return can be very useful for a tankadin. Could also be used by a healer (perhaps a Paladin or Shaman) that likes to do some melee between healing spells.
This item used to have 11 stamina and 5 spirit in addition to the proc, which made it a very good tankadin weapon.
Patch 1.3.0 (07-Mar-2005): Fixed a bug with Fist of Stone that caused it to have stats that it shouldn't have. Existing Fist of Stone items have not been changed.