Mighty Versatility

Consider this, you can swap weapons and off-hands in combat. Let's say you've overspent your mana (emergency heals, burst damage, whatever your reason) and want to quickly gain it back. Buy a cheap green "of spirit" 1H and off-hand. Enchant the 1H with this. When you need mana back, equip the greens and start wanding. Also as a priest with Spirit Tap who's grinding, dps them down to 5/10%, swap, wand (while 5 sec rule clears) and when they die, watch your mana flood back. You could even have a spirit tap gear set. I know that with the addon "outfitter", you can select a different set of gear while in combat, and as you drop out of combat, it will auto-swap your gear :)

With the changes to Spirit-based talents in Patch 2.3, I'm really hoping to see a BC upgrade of this enchant

best spirit enchant so far, great for innervates and evocates.

Too bad it costs so freaking much. On my server, the mats for this would cost almost 3x as much as 30 int, a TBC enchant. I wish there was a BC version of this. :/