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A trinket that provides high spellpower and a wealth of mp5 since it acts like an Illustration of the Dragon Soul, this is very powerful. 288 passive spirit.
It has an on use that can be macro'd to your spells to make sure it is constantly active and providing regeneration. Overall, this is the best holy trinket in the game. According to WowHead's comments and math this trinket can be worth around 284mp5 factoring in an average number of SOW procs, mana tide totem, and regen from the crit this gives.
From logs the on use is roughly 5-6% healing on an AOE damage fight like Sindragosa. If you replaced Meteorite Crystal it's 5% healing (this trinket) vs ~10,000 mana (2 Meteorite uses plus its intellect estimate, increase mana for longer fights like LK). This is a good trinket for fights where mana doesn't matter. Otherwise sticking to regen is my preference.
This trinket is better than a heroic Solace if a fight is less than 4 or 5 minutes. After that, Solace pulls ahead in regen.
This short analysis ignores the fact that this trinket also provides a powerful 600 spellpower on use effect that helps during Divine Plea usage and other burst healing scenarios.