It depends on whether you had had too much withheld in the past, there isn't an easy answer.
For most people, the $400 reduction in withholding will only mean a slightly smaller refund. If there are young children in the household, small increases in the Earned Income Tax Credit should offset the lower withholding.
For folks who only had a tiny refund to start with, the decrease in withholding may mean they end up owing a bit.
The folks who will be hardest hit are those with more than one job at a time in the household, as the combined reductions will cause their refund to shrink considerably.

