But which one of these is the better option? Well they each have their own advantages.
401ks for instance give you a lot of tax breaks. All the money that you invest into a 401k are invested before you have to pay taxes on it. So, you start off ahead. In addition to that you can grow your money tax free until you take your money out. Private brokerage accounts have none of those advantages.
That 401k information makes opening a private account sesm like a bad idea, however the advantage of having a private account is that you can invest into individual stocks and are not limited to just investing into specific mutual funds. This can be a major advantage because an account earning 15% a year that you have to pay taxes on will still outperform a tax free account making 6% a year.
Ideally investing into both can be a great idea. But for the average person without much experience in the investment world a 401k or a similar plan is probably what they should focus on.