Priest T16 2P Bonus (New) Serendipity also increases the healing of your next Greater Heal or Prayer of Healing by 50% per stack. While Archangel is active, your critical chance is increased by 10%.
Priest T16 4P Bonus (New) Circle of Healing and Prayer of Mending casts increase the effect of your next Holy Word spell by 50%, stacking up to 10 times. While Spirit Shell is active, you gain 10% haste and 3,500 mastery.
I love how the sets look on the disc side of the house that 10% haste for more shields!