I get that for some "big corp" jobs could be more rewarding, and I am sure some are. However, my experiences at "big corp" jobs have been nothing but disappointing. For example, I've worked for/with incompetent managers who are good at "gaming" the system to be where they are and totally suck at managing people, incompetent colleagues who create more problems than solving any and do not seem to want to learn new things or correct their mistakes.

Startup jobs are definitely more stressful, and co-founders have enormous impact on the company, but I would always take startup jobs, where I can work with and learn from smart people (as long as there is a good team chemistry and no one is an asshole), over "big corp" jobs.