Working for a startup is a sucker's game. Even assuming it succeeds, with the amount of equity a typical employee holds and the size of an average buyout, the best-case scenario is that you'll emerge with a pittance after years of very long workdays. More likely you'll end up with nothing, and little professional respect for having spent years at a company few people have ever heard of. The odds are really only in your favor if you're a founder, not an employee.