If you control your commander you get to do both modes, which gives you an incredible amount of card advantage in a single turn
Anyway, of all the options open to players round one, the top performing deck the first round was
Additionally, I think it is a very flavorful card, as the two life it costs to cast beautifully illustrate the characteristics of the black color in Magic: The Gathering
Meanwhile, Oblivion Ring gives us a main deck answer to non-creatures like planeswalkers, artifacts, and enchantments, and works well with Flickerwisp, since we can exile something in the early game and then, if our opponent plays a bigger threat later, reset the target by exiling it and returning it to the battlefield
Either way, we have a sort of downgraded Goblin Rabblemaster effect in creating Goblin tokens
Its nice to see Addendum make a comeback, considering both the Brokers and Ravnicas Azorius (for whom Addendum was their mechanic) control the legal systems of their respective worlds