The 401 (k) is simply objectively better. Both 401 (k) plans and IRAs have valuable tax benefits, and you can contribute to both at the same time. The main difference between 401 (k) and IRAs is that employers offer 401 (k) plans, but people open them (using brokers or banks). IRAs tend to offer more investments; 401 (k) allow for higher annual contributions.
When you change jobs, you generally have four options for your 401 (k) plan. One of the best options is to transfer the 401 (k) plan to an individual retirement account (IRA). The other options include withdrawing it and paying taxes and a withdrawal penalty, leaving it as is if your former employer allows it, or transferring it to your new employer's 401 (k) plan, if one exists. If you have access to a 401 (k) plan or similar for employers and your employer offers you an equivalent contribution, the best starting point is to deposit at least up to the matched amount.
With a traditional 401 (k) plan, you make contributions with money before taxes, so you get an advance tax break, which helps lower your current income tax bill. Your money, both your contributions and your potential earnings, increase with deferred taxes until you withdraw it. At that point, withdrawals are taxed at your current tax rate. There may also be state taxes.
The typical hybrid fund of a 401 (k) plan is 0.19 percentage points cheaper than the same fund available to IRA investors, according to the Pew study.