1. Salary. Startups always seem to offer lower salary in return for said equity.
2. Career development. Startups demand that you build somewhat hacks solutions for the sake of time. In many instances you might not get the opportunity to learn how to do things right. Too much of this and you get used to building hacks products.
3. 80-hour work weeks might not be the norm, but what about 60 hour work weeks? that's a deal bresker for some.
4. Diversity. Startups are notorious for hiring people just like the founders.