SUBREDDIT: r/personalfinance
TITLE: Post 86 After Tax Contributions
POST: Many people advocated the following:

1. 401(k) up to the company match
2. Max Roth 401(k) (or traditional I don't want to debate that now)
3. Finish maxing out 401(k)
4. Max HSA contributions (if an HSA is the right choice for you again don't want to debate that now)

Now let's say I've done all of that. And lets say my company allows me to contribute to a Post 86 After Tax account [up to $51,000 MINUS all employee & employer contributions to 401(k)]

Can someone explain to me what the benefits of this After Tax account are versus a normal taxable account?

How about the disadvantages?
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TL;DR: 
We talk about lot about 401(k)s, IRAs, and even HSAs but I haven't read anything on this subreddit about After Tax Contributions (Post 86 specifically)