For the Roth vs traditional, I would try to think about how much money you'll have in retirement, the tax rate now vs best guess at what it'll be in the future, and then how much you'll need to take out each year. If you're a high compensated employee then your tax rate now is high, so if you go Roth you're paying high taxes, but if you retire and are in a 12% bracket and you're taking money out of your Roth then you paid more in taxes. If you have a 401k and deduct from taxes now and pay 0% now and when you retire you're in 12% for 401k withdrawal then you made out well. So as much as you need to determine whether it's worth it now and the tax rates, you also need to think about what your tax rate will be at retirement.
DW and I are at the Roth IRA phase out area, so well compensated, we've always maxed 401k and Roth IRA when we are not phased out, so we are at top of what is now 22% bracket I believe. With the tax cuts and what I project we will have in 401k's at retirement I decided to hedge my bets and put my money in Roth TSP (equivalent to Roth 401k) as even though we've got a decent salary and are paying higher taxes, if we keep working, our 401k's at retirement and what we could withdrawal may have us at above our tax rate now, so we're splitting the difference.
The idea is that when we retire, which will probably be maybe in 10-17 years for her and 17 years for me and will have another 15 years before RMD's, that we can convert or take money out of 401k's at a low tax bracket and continue to let Roth grow as much as possible for tax free money into older age. Anyways, you get the idea, try to think about what your bucket will be at retirement and guestimate if your tax rate will be greater, same or less in retirement. I like separate pots of money so you have options at retirement based on tax rates, as they will change over time.
Remember that it doesn't have to be an all or nothing. When I started contributing to to Roth 401k (Roth TSP) a few years ago, I started w/a small amount in Roth, most in 401k, then split down the middle a year later, then w/tax rate cut of this administration I put most into Roth.
