Quote Originally Posted by Ozymandias View Post
It really depends. Because let's assume that the opponent has played 3 accelerants, so he has three mana in his mana pool, and is obv. holding one kill condition, so that he has 3 unknown cards in hand. Then, he plays a 1-mana accelerator.

If you counter, you basically lose. Because your opponent has, a hypothetical 11 win cons, 4 street Wraith, and 45 acceleration, so that there's little to no chance that he's holding at least two more win conditions, which is what you would need to have your counter be effectful. Otherwise, he ramps up to that 4 mana through your counters and plays what he was gonna play anyway. 8/11 of the time. Or, he could cast Burning Wish, and find something good anyway.
Not really. If you counter the accelerant, he has 2 mana in his pool and 3 cards in hand. To win from this situation, he needs those 3 cards to consist of 2 accelerants and EtW. If those are the cards he has in hand, he wins regardless of which spell you counter. But if he only has 1 accelerant, he fizzles. Or, if has a Wish or a Belcher instead of EtW, he fizzles for the turn. By countering that accelerant, you have the greatest chance of stopping the combo.

Quote Originally Posted by Ozymandias View Post
So, the only time it's right to counter going above four mana is when it's with a Seething Song
As described above, this isn't true (unless you have an answer to EtW).