Roth 401(k) vs. Roth IRA?

Have you decided that you want to contribute to retirement but aren't sure whether to invest in a Roth 401(k) vs. Roth IRA?  
Greg Turcotte of Alpha Financial Partners explains that a Roth account is contributed to with after-tax dollars.  Not only does the investment grow tax-deferred, but when you get to retirement, you can pull the money out tax-free.  
One of the main differences between a Roth 401(k) and a Roth IRA is the contribution limit.  You can put in up to three times as much in a 401(k) compared to an IRA on an annual basis.