There is no choice about what turn to sacrifice it.
The chosen recipient must be able to legally be enchanted by the Aura, so a player or permanent with protection from one of the Aura's qualities can't be chosen this way
It has quickly earned a reputation as a staple of competitive Standard and Pioneer, and it even sees play in Modern and Vintage
I'm not a fan of the constant power creep we've been seeing, but in today's Commander it feels ridiculous that they're putting one out that costs eight
In the case of the former, its because the best choices vary not only by color identity, but often by specific deck building limitations: Seismic Assault and many other red effects want you to play an extra-high land count, while a black deck with reanimation and Tortured Existence obviously cares about discarding creatures
Blue Consecrated Sphinx This would be stopped by the fact that it cost except for the fact that every time I see anyone playing it, they're cheating it out