2013-10-17 : If there are two Primal Vigors on the battlefield, the number of tokens or +1/+1 counters is four times the original number. If there are three on the battlefield, the number of tokens or +1/+1 counters is eight times the original number, and so on.

2013-10-17 : It doesn’t matter who controls the tokens or the creature that the +1/+1 counters are being placed on.

2013-10-17 : Primal Vigor affects permanents that “enter the battlefield with” a certain number of counters. For example, if a creature would normally enter the battlefield with three +1/+1 counters on it, it will enter with six +1/+1 counters on it.