Major Spellpower

Obviously the dps caster enchant of choice, not matter what type of player you are (raider, PvP, or causal).

Actually, spell hit rating does nothing to reduce a target's resistance to a particular school of magic. It only determines whether or not the spell lands in the first place. Spell penetration is what lowers the impact of a resistance to a school of magic. For example, assume the boss mentioned above, Krosh, has 25% Arcane resistance. The mage tank would need roughly +210 spell hit rating to decrease the chance for his spell to miss to 1%, and then he would need additional spell penetration gear to make the spells hit for their full effect.
Spell penetration is more useful for PvP, as bosses rarely have resistance, and spell hit is more useful for PvE, as you only need about 50 spell hit rating for PvP.

That being said, this is the best hands enchant for any spell caster. The recipe itself requires the Enchanter to be Honored with the Keepers of Time and have 360 skill. Achieving Honored (and even Revered) is not a difficult thing for players to do. In fact, more than likely the player will hit Honored just by doing the Karahazan attunement quest line.

Spell hit rating doesn't effect partial resists, just full.