Big Question here

Roth -- tax rates are going up so we can pay for all these sickly Boomers... take the hit now.

I think there are ways to rollover, probably through paying the taxes. That's something I would consult an adviser about though I'd guess someone on here could help point you in the right direction better than myself on that one.

That said, I personally have a Roth. I absolutely won't finish in a lower tax bracket than I am in now and I like the idea of compounding growth over time that is not taxed. I doubt they will have lower taxes when I retire than now. It's really a preference as to whether you value the tax break you get now more than down the road. So, if your tax rate is high currently you'll probably, without knowing anything else about your situation, prefer to contribute pre-tax as it lowers your taxable income. If you are younger and in a lower tax bracket, it may make more sense for you to pay the lower tax rate now and pull it out tax free down the road thus saving any taxation on the gains you've made over time.

You'll have to do your own math on the options, but those are the absolute basics on the different considerations you should have between the two.

I'd go roth if you qualify. Ideally when you retire you'd want a combination of Roth and traditional accounts to draw from, which will allow you to manage your tax expense.

Hopefully you won't always qualify for Roth, so I'd contribute while you can. I wish I had that option when I qualified.

You can roll traditional accounts into Roth's, but all taxes are due immediately.

jankynoname

Roth -- tax rates are going up so we can pay for all these sickly Boomers... take the hit now.

This. I think what a lot of people overlook is that putting post-tax money into a tax free account or pre-tax money into a taxable account yields the same results given a) the same compounding rate, and b) the same tax rates now and in the future. So your decision should come down to a comparison of the rates. It seems common sense but I always see comments like "I'd rather put more money in and have it compound, etc". It mathematically wouldn't matter given the prior two assumptions. Rates going up- Roth, down- traditional.

Dr. Seuss is right so the following is why I use a traditional, which may or may not make sense. I am in a middle tax bracket now. Hopefully, I will be in the highest in the future, which means I will be making more money and (hopefully) will not "need" my IRA. There's also a chance, I suppose, that I will be in a lower tax bracket. If I'm in the higher tax bracket, I could afford to be losing a bit of absolute money from the IRA to taxes. Conversely, if I'm in a lower tax bracket than I am now it means I'm making less and so would want to be maximizing the money I'm receiving from the IRA. This reasoning doesn't take into account the fact that all tax brackets could be shifted up, say 10% or something, as tax rates change because it is very hard (impossible, I think) to predict what tax rates will be 40 years from now. Also, I am assuming my return will be the same regardless of type of IRA I use.

TL;DR - a traditional IRA is a hedge against having a lower salary in the future.