Roth vs. Trad debate has a lot to do with your tax rate now vs. tax rate when you retire. Well, that assumes good knowledge of future income as well as future tax rates. Good luck with that! As such having some Pre-Tax and Post-Tax retirement money means you have diversification there as well such that when you are 65 and a tax rates are expected to go up/down across the board because of a new President etc., you can have flexibility to decide if it is better to be taxed this year or next. The Roth also has no RMDs.