I have a friend who gets part of his compensation as stock, but the company is not publicly traded. There's the vesting part, which he knows upfront, but the worst of it is that the valuation seems somewhat arbitrary, and he can't sell when he likes.

Now I understand they give the same valuation to everyone, as estimated by some third-party, but the issue is that even after the vesting period, he's not able to sell his stocks as he pleases if he needs the money. There's a pretty convoluted process, where he basically can only do this once a year and has to let someone know (don't know the specifics) ahead of time that he's looking to sell.