"We pay no income tax on dollars going in, an immediate savings of up to 39.6%, the highest marginal rate."

Maybe this was true 6 years ago when this article was written, but now there are income limits for the tax deduction on IRAs. The limit depends on if you have a work sponsored retirement plan available. There is a good change you wont get the upfront tax savings.

The article also says this:
"If during your retirement years you expect to earn less than ~$90k/year, staying below the 25% tax bracket, then all Long Term Capital Gains and Qualified Dividends are already taxed at 0%."

I'm not convinced you can assume that will be true 20 years from now.