Also, FAANG will negotiate offers against fringe benefits. They won't cut you a custom 401K deal, but they will beat any offer by 20%+ and include the post-tax cash equivalent of better retirement packages in that beat. If you ask for it and if they want you badly enough.
Assuming you can get a gross offer that matches net, having the money in post-tax accounts is better because the tax rate on the 401K at withdrawal will likely be higher than the 15% capital gains rate.
