You'll need time to recover from the tax hit that comes with a Roth conversion. In general, if you intend to start tapping into your retirement funds within 10 years, it's not a good idea to convert. There won't be enough time for the money to grow and make up for the immediate tax hit. But if you have 20 or more years before you'll start making withdrawals, the math might work, especially if your income-tax rate declines in retirement. The one time a Roth conversion is certain to pay off is when you never touch it and leave it to heirs. With a Roth, you are not required to make annual withdrawals, as with a traditional IRA. You can leave the full amount to heirs tax-free, and they in turn can leave the money alone to grow tax-free over their lifetime too, although they would be subject to mandatory minimum annual withdrawals. This makes the Roth IRA a great estate-planning tool.
See if you should convert to a Roth IRA:
Introduction: Traditional IRA vs. Roth IRA
What Are Your Tax Assumptions?
How Will You Pay The Roth Conversion Tax?
Will You Convert Your Entire IRA Or Just Part?