Pros
Benefits are great. You get 2 weeks free vacation from the summer and winter shutdowns and plenty of vacation time. Pay is generous even if it below industry average If you're in the right group, you can do interesting impactful work. Generally, your coworkers will be kind and supportive. Management does seem to care about people's well-being.
Cons
Your career will live and die by who your manager is and what projects you are assigned to. You'll notice the same handful of people get moved up the corporate ladder while everyone else stagnates. These are rarely the most talented workers, just the people who are good at spinning their BS. If you work on something outside one of the money-maker drugs, be prepared to hate your life. Your coworkers will be incompetent and/or contractors from India. Management won't care about you until your team inevitably make a mistake from being understaffed with no talent. Job duties are dictated by complicated SOPs that don't have enough information. Small number of people become invaluable because they understand how work actually gets done. Don't expect to do actual science here. All the technical experts have left Lilly years ago. You'll join focus groups that sputter until management has enough to spin to their bosses.