How does work ethic compare between H1B and American hires? Even with language and culture issues?

I'm not an H1-B, but I am on a skilled migrant visa in a different country. While I'm not constantly thinking about it, I'm keenly aware that my immigration status is directly tied to my job. No job, no residence permit. So at a minimum I would say I have an incentive to not get fired, and the best way to not get fired is to be someone worth retaining.

In my experience H1-Bs know that the consequence of losing their job could mean being forced to leave the country. Management knows that too. Obviously this affects the incentives and behavior of both the manager and the employee.