Combo decks value consistency, speed, and resilience: the deck should be reliable enough to produce the combo on a regular basis, the deck should be able to use the combo fast enough to win before the opponent, and the deck should be able to withstand disruption and still win . Link I think this is way too long, and it suffers from some of the same problems as some of the definitions above
Such a gorgeous set though
They still present an attack threat if left unchecked, but in most cases, you'll be using them for their +2,000 Counter effect
Eventually it was too good even for Vintage and it proves that no matter what there are some abilities that are just not meant for this game we like to play
This is a bomb in EDH builds of this deck but for cube it is typically a lot worse than targetted spot removal
Personally, I think they're great