If you are leaving employment on unfriendly terms, it will serve you well to sign
nothing without consulting an attorney (preferably one specializing in employment law and contracts).
(This, of course, does nothing for what you may have signed upon becoming employed, nor what they may have shoved under your pen while you were employed.)
Generally, the incentives are relatively small, and what you are giving up is potentially rather greater. This is why they attempt it -- risk reduction. I'm aware of proposed agreements that, for a few thousand dollars in a one time payout, cause the formerly employed to abrogate supposedly all rights to sue, on any basis.
Granted, that may not be entirely enforceable. But it's another considerable hurdle to surmount if and as you feel and determine yourself to have been wronged. First, you have to attempt to break out of the binding arbitration -- if any -- that such contracts impose.
I'd rather have a few expensive suits and management sweat a bit more, if nothing else, in such circumstances. Tie them up with more paperwork and tracking. If nothing else, it helps to keep them on their toes and perhaps less likely to screw the next guy.
And yes, again, in such circumstances, somewhat of that perspective is prescribed. No matter how well you may have gotten on with your co-workers and immediate management, the company is not / no longer your friend.
You will feel and manage much better if you have prepared yourself for such an event, however unlikely you may currently consider it to be. Have enough cash and liquid assets on-hand to ride out such a period of unemployment. Don't assume you will have unemployment benefits when making such calculations; if a business decides it wants to screw you, they can at least delay the granting of such -- though you should contest such a tactic. (And, in that regard, documentation is your friend. Keep printouts of relevant material. If you feel things are going south, keep a separate, datestamped journal documenting specific events in detail.)
If you have assets on hand, you will feel less motivated to take such a payout, especially not one that is rushed upon you with a very limited window for consideration. You may also decide it is worth the money to at least consult with an attorney (that you are paying by the hour, not on contingency) for an independent and professional opinion.
Many people on HN are at least ostensibly "professionals". A few thousand, for a regular, full-time employee, should not make or break you. Look towards handling your end of such an employment arrangement professionally.
Even if it costs you a bit of money, you will likely feel much better about yourself and how you've handled the situation.
And that self-esteem, aside from any (frankly, unlikely) favorable financial outcome, can pay off significantly as you move on with your life.
Just my opinion...