[ChrisCinelli]

If money is the main driver, look at the package they give you: that is pretty much what you get. And if you look at startups in general, most of the people end up with very little from their stock. Funders are in a slightly better position.

If money is not the main driver, ask yourself: what would make this experience negative for you? How likely is to be worse than... (you need something to compare to) ?

In lack of a more compelling alternatives, I do not see why this could not be a great learning experience for you.