The dependent care credit is a sliding scale of between 30%-20% of qualified expenses, depending on income.The sliding scale is shown on page 1 of form 2441. Most of the time, I would expect a middle class taxpayer who can afford to keep 2 kids in care would be at the 20% end of the range (which would equal a credit of $1200.
Because the FSA saves you on social security and state income tax as well as federal income tax, I would expect most people to save between 22% and 37% on their taxes (depending on tax bracket and what state you are in). So for almost everyone, the FSA will save more than the direct credit. But the credit is available if you aren't enrolled or can't enroll in an FSA.
Also, some states may have a dependent care credit that is based on a percentage of the federal credit (NY does, you would have to look up your own state) that adds to the savings and closes the gap somewhat between the FSA and the credit.
