One size doesn't fit all when it comes to taxes. I guess it depends on if you are able to realize and save the money from adjusting your withholdings. For us, when DH adjusted his, we owed the IRS $350 the next year and the State $250. So that was hard on the budget. It is better for us to let the govt use our money for a little bit and then get a refund. We don't get $6000 back. Not even close! 
I think people need to understand that financial circumstances can change during the year that will automatically change your exemptions and withholdings or your income bracket. (No tax advice given here). For example, having a baby (or having a child no longer be your dependent), losing your job or selling stock and earning capital gains. But when our family goes from a $500 refund to owing $350 and then having a baby and getting a $1200 refund to adjusting and then owing $300 again, I would rather just get my refund. Having an extra $100 a month is not enough to make me adjust withholding (guessing game) or change exemptions again and then owe the govt. For me, that's worse than letting the govt "borrow" my money for 12 to 15 months and then give it back.
We sold some stock in 2007 so we didn't make any adjustments. We had a bigger refund in 2006 than I would have liked (not that I complained about $2200 but it all went to the credit card) because we had a baby near the end of 2006. Knowing we had to sell some stock and have capital gains plus DH got a raise when he got his master's degree in 2007, we didn't change our W4 after ds #2 birth so we would possibly break even for 2007 (or get a little back). We will see this year. My goal is to NOT OWE THE GOVT.