There are definitely benefits.
On your CV:
- If you've worked for a well respected company for a good amount of time, it is a good reflection on you.
- If you can show steady career advancement (promotions, increases, etc.) in such a standardized environment, even better.
- If you have contributed to a well known project, people get excited.
- For me, this was a bigger factor in getting my current job, than my qualifications.
Personal experience:
- You can get experience working at scale (valuable experience if in the future the project/company you work on needs to scale)
- i.e., working on a code base that is actively contributed to by 1200 developers, including the integration, QA and production release cycle associated with such a large project.
- Working on a massive code base that you couldn't possibly fully understand (O(10's of millions of lines of code)).
- Managing requirements and priorities (or just seeing how these are managed) for such a large environment.
- Collaborating with other groups and teams, often from other disciplines, on the same project.
- You get to see how large organizations and projects are managed (both the good and the bad) from the perspective of the engineer/developer. Getting actual management experience in this environment is also invaluable.
Networking:
- The number of people you meet and interact with in this type of environment is huge. The people who work there eventually go to other companies, and you can build up a very large network of contacts.
- Reputation: building up a solid reputation in a firm of 20 people is great, but if you do it in a firm of 10000 people, the entire industry will likely know you or know of you.