In a recent NPR story about how much more vacation time Europeans take than Americans, economist Lester Thurow described it thus:

To feel that they're getting the most out of their vacation time, Americans (in general; it's a generalization, OK?) want accessories like powerboats. Europeans (in general) are perfectly happy to spend their vacation in a canoe, and so can afford to take a lot more time off work since they don't need to pay for the boat.

Thurow also pointed out that, while there is plenty of anecdotal evidence that longer vacations make one more productive when back at work, there is no hard evidence to support this notion, and so one cannot say which work ethic is 'better' for an economy.