posted: Dec. 5, 2007 @ 4:23p
You can take contributions from your Roth IRA before age 59.5 without penalty or tax for qualified education expenses (paying for college for kids say) or for purchase of 1st home. No such case for Roth 401k, if you take money out for any reason before 59.5, you pay 10% penalty and have tax liability on earnings. Also after 5-yrs, you can take out contributions from Roth IRA without penalty. You can't take out earnings outside of qualified distributions but contributions you can take out if you need to. You're also not restricted to your employer's investment choices in your Roth IRA compared to Roth 401k.
For Roth 401k, one main advantage is you don't need to worry about income limits for qualifying.
Also, the contribution limits aren't the same. For Roth 401(k), it's $15,500 per year and only $5,000 for Roth IRA. Even more so in favor of Roth 401k, if you're taking into account catch-up contribution limits.
Technically, the Roth 401k has the potential issue of requiring you to take minimum distributions after age 70.5 (same deal as regular 401k). But since you can rollover a Roth 401k to a Roth IRA directly (but not from Roth IRA to Roth 401k) or even you can roll Roth 401k distributions into a Roth IRA, that issue is really moot as long as you have a handy Roth IRA account available.
I like this presentation from the IRS on the comparison: Roth IRA vs Roth 401k
I'd say if you qualify for Roth IRA contributions, it's a more flexible vehicle IMO. More choices for investment, cna take early qualified distributions, can take contributions out after account has been opened for 5-yrs. Aside from contribution limit and income limit for qualifying, I'd say Roth 401k is for after you've maxed out your Roth IRA.
Of course, if there is company match, that's another issue. Then you'd put first in Roth 401k up to company match, then Roth IRA up to yearly max contribution, and if necessary after that back to Roth 401k.