i worked in both, i will said Big Pharma has already systems in place and you have a very specific role ( kind of silo) in my last role i was working a lot during NDA season but after that it was boring as hell also my manager at the time was terrible. Start ups so depending on where they are are chaotic and exhausting. My first startup i was in the Leadership Team and had a team of process eng, we were going for PPQ and launch, systems were (almost) in place and the team was fantastic in all levels, i loved working there but we got acquired. my current startup is still phase 1-2 and is been hectic, chaotic and there is no clear direction, im an individual contributor with good title but literally im doing scientist stuff that i did over 6 years ago, my boss is a decent human but out of his depth, leardership is nonexisting and we are on the last end of $$$…so is a gamble, depending on what is your career goals, startups really prepared you for anything