What I usually tell new grads is: Get offers from both, and take the job that has the best potential person or people that you'll be able to learn from. There are a bunch of ways you can research this. Try asking people on the team to tell you who they've learned the most from in their career.
Do not take a job where you'll be a lone wolf. As a new grad your goal should be to find great people to work with and learn from them.
If you want to have a balanced career you should try both big corps and startups, but ordering doesn't matter.