The FSA is better for anyone whose income is more than about $18,000 (last time I did the math.)
The FSA can be used on a max of $5000 of expenses regardless of number of children. The dependent care credit covers a maximum of $3000 expenses for one child or $6000 for two or more. If you do provide care for 2 or more children, you can max out the FSA and then use the next $1000 of additional expenses to get the dependent care credit (so you leverage a total of $6000 of expenses.)
In your case, the FSA saves you 25% federal tax plus 3-10% state tax depending on the state on the first $5000 of expenses, and the dependent care credit will pay 20% of $1000 more; while using the dependent care credit only without the FSA would save you 20% up to the first $6000.
