I've been back and forth between startups and corporations. I think I know what you mean in technical terms; that corporations use more advanced (rigorous) processes and tools and so it feels like you're learning more (it feels more precise/correct) - That said, I think that a lot of the stuff that you learn in big companies are anti-patterns when you consider the big picture; a lot of the time, you learn technical solutions to problems which don't really need to exist to begin with.
For example, one reason why many corporations push really hard on having 100% unit and integration test coverage is because they have such high employee turnover that they can't rely on their engineers to maintain their own code; corporations have to assume that engineers who work on their projects are completely unfamiliar with the code - In this case, automated tests are the only way to maintain the integrity and stability of the code base. The time cost of maintaining all these trivial unit tests is ignored (even though the cost is actually very significant; not to mention that these tests lock down the code and thereby discourage refactoring and experimentation).
Corporate processes are designed around the assumptions that engineers don't care and can't be trusted. This is a very inefficient approach to building software.
Personally, I'd rather my project have code with 0% unit test coverage written by a team of involved engineers than code with 100% test coverage written by a team of indifferent engineers.