Never take the counter offer.
When it is offered you will have two jobs to choose from.
If you take the counter offer, they will build up your replacement and drop you when it is convenient for them and inconvenient for you. You will have zero jobs to choose from.
That is just general advice. Not something you need to worry about. The only thing useful about the counter offer from Fiserv is that it is good for a laugh.
Excellent advice pulled from +1j2daWqf thread.