It purely depends on how do you envisage your journey. Depends whether you want to be a fish in an ocean, or a pond. The learning is a lot more faster and hands on, in start ups. You get to work with the senior management directly and you can make a difference, if you want to.

If you are looking for a stable job with guaranteed monthly salary, then join a corporate. Corporate gives you a steady growth (not exponential compared to start up), gets to work on a smaller piece of the whole project.

The choice is completely yours. Go thru some of my articles that might open up some thoughts for you.

https://www.linkedin.com/pulse/journey-sme-vs-corporate-shivadhar-soma?trk=mp-reader-card

https://www.linkedin.com/pulse/what-happens-when-employees-become-stake-holders-shivadhar-soma?trk=mp-reader-card