If you are specced Seals of the Pure and have the judgement glyph it makes a considerable difference. I think without SotP or atleast 3pts in it, it is kinda a wasted Glyph. I personally don't feel the need to use the RD Glyph so I stick with the SA one. I have mana problems in Naxx and Sartharion but on Malygos not so much as well as the Taunt Glyph there really won't do much.
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Regretful - Female Blood Elf Paladin of Mannoroth
Subject - Male Human Paladin of Arthas (Sold Pre-2.4)