Well, that depends a bit on your goal.
If you need their parties to still run higher quests than they can now, that 2%  boost in power to each party member is nice.
And 1850 item power for a legendary Shielding Ward is quite decent (lower level Protector items, such as the Protector shield, are a bit less suitable on lower end heroes, since those cost them a bit in personal power for that slot and a party is kind of as weak as its lowest power member...
Legendary Prayer Ring is 2200 power, but as long as the hero and his/her gear are at least (2200 - 1850) * 100/2 = 17500 power combined, that 2% from Protector should buff even that one hero more than that 350 difference (before taking into account the buff to the other party members) .
If you already have plenty of power for the quests you want to run, then obviously the Prayer Ring and its Revive I is the better choice.
 or was it 2.5%? there was a forum topic somewhere about odd display rounding of percentages of some skills... darn you hazy memory!
as of 2016-09-11: Player level: 44, City: Eolythes, Blueprints: 517, Mastered: 419, Crafted: 78.61K
(except for tier 1 and some tier 2 artifacts mostly running my shop/gearing self sufficient)