I don't think it was satisfying at all (new ending or not, I'm done with Mass Effect 3), but I wouldn't rate that as a quality problem. Especially because there are people who apparently enjoyed it. That to me says it's more a matter of taste -- this ending wasn't for me, and that's fine. Not everything has to be for me.
I honestly have not seen one in-depth argument in favor of the endings.
I would love to read one. As for the quality issue, I guess it could come down to what faults I think the endings have? I mean, as part of the fiction, I think they are contrary to what everything Mass Effect is about. They don't seem to fit within the established universe.
But again, that's just me. That's why I don't think the current endings are a good piece of content.