It's taken over Standard. It's a solid EDH player. It's the second-best four-mana artifact in Modern that can only be activated as a sorcery.
Okay, that last one, while probably true, doesn't mean much.
Anyway, Whip of Erebos.
Right now, everywhere in Standard. Even if we make an exception for the unique format of Worlds Week (no time limit and then Unified Standard), we've seen this card everywhere. Sure, at Worlds the grindy Whip decks experienced an advantage since they didn't have to worry about going to time when they played two-hour matches, but we've seen the Whip (and often Sidisi) decks stick around since then.
You can read the full post here.