I think it's incorrect to compare marginal rates as well. It makes more sense to compare your Effective Rate in retirement versus your Marginal Rate of today. This article explains the math: http://www.gocurrycracker.com/roth-sucks/

Your effective tax rate is likely to be much less than your marginal rate.

Also, for anyone interested in financial independence and simple investing with your 401k and IRAs, I'd like to recommend the Stock Series here: http://jlcollinsnh.com/stock-series/