What really makes the difference in terms of maintainability is how easy is to run the tests and how much they're automated. What's important is to have test c

What really makes the difference in terms of maintainability is how easy is to run the tests and how much they're automated. What's important is to have test coverage and to keep exercising it when the code changes. The best way to achieve this depends case by case. Sometimes unit tests are better, sometimes integration test is the way to go.