Benefits of a Roth 401K vs a Traditional 401K?

Not paying taxes on it later, but that is really a discussion of your current tax bracket versus the expected one at retirement.

Is the company going to offer you the same match on the Roth? Some do. Some don't.

All things equal, most advisors suggest a (not necessarily equal) balance between the two. As well as not knowing your income at retirement, you also have no way of knowing what the tax rates will be then. Having balanced contributions gives you the option of mixing tax free income with the taxable upon retirement. And right now, the traditional 401 contributions will be lowering your taxable income.

It's a way to hedge your bets, to have some in a traditional and some in a Roth. In addition to the tax deferral differences, Roths don't have RMDs.

Also, someone noted checking on the match provisions. If a company does match Roth deferrals, note that the match will still be in a traditional account, even if your deferral is a Roth. The only way around this, and I don't know of any companies doing this, would be for the company to tax the Roth match, essentially phantom income. I would not do this.

But if you are trying to split your total match plus deferrals in a certain percentage, keep that in mind.

For myself, I've stuck with the traditional 401k. The 401k deduction combined with my mortgage interest deduction reduces my income taxes a considerable amount.

The thing is who knows what income rates, tax laws, etc will be in 20-30 years.