I chose the ritual with all but one of my Wardens. Reasons (differently weighted for different Wardens):
(1) The DR outcome is plainly more interesting than the sacrifice
(2) I am somewhat allergic against the heroic sacrifice trope since it's all too often used for heavy-handed moralizing.
(3) I find it fundamentally desirable that a human takes ownership of some powers formerly reserved for the gods. Too bad about the reversal.
(4) It is what Morrigan wants.
(1) Impossible,the outcome is the same and the two different scenes share pretty much the same dialogues conversations,due to the fact that the DR bring us to a nullification.
(2) Is not the case of an heavy handed moralizing, GW are not meant to be heroes, the Ultimate sacrifice is just a weapon to eliminate the essence of the Old God, the sacrifice is there for people who do not despise responsability as GW not for "heroes".
(3) Aside from the fact that we discover that Kieran gain little if nothing from the AD,due to the fact that they are two separate entities,Urthemiel is Urthemiel and he is just using the boy as a vessel,
he do not even thinking twice before to abandon him and reach a more powerful host,the old god never grant his power to the boy until the very end in which he travel across the eluvian,he just share some of his knowledge.
(4) I couldn't care less of what Morrigan want.