Open Focus and Mindfulness are not distinct and competing practices but rather highly complementary.
Mindfulness helps us to learn to pay attention to our experience and to notice how we are relating to this experience. Open Focus then builds upon the benefits and skills of Mindfulness by training us not just to pay attention but to be more aware of how we are paying attention and to be more flexible in our attention styles.
We then have the benefits of two complementary practices available to us; learning to pay attention and being flexible in how we pay attention. We could say that Mindfulness is an excellent foundation for Open Focus training and that Open Focus helps us to get the most from Mindfulness training.