Back to the discussion on hand:

It seems to me that Tendrils combo can do a few things on its turn.
A) Go all in - This is basically trying to win and losing if your opponent has more disruption than you have protection. This is more and more effective with more turns of Set Up.
B) Bait - This would be something like Chanting when you can't go off so you can Extirpate their FoW, or early game dropping an IGG so they either have to FoW or lose their land drops/aggro.
C) Set Up - In some decks this is just "Draw, Go", and in some forms of Combo it's "Infernal Tutor for Chant #2, go". Either way, setting up will always make the "All In" play more effective, however, this also gives your opponent more time to stop you. The fact is that the better at setting up a Storm Deck is, the better it will be.

Therefore, it seems to me that the best Combo deck in the format is the one that can Set Up the fastest, outpacing the disruption of the deck that is trying to stop it.