When should I publish in interdisciplinary versus subject-specific scientific journals? Most science research is published in subject-specific journals, of which there are many. However, there are a relatively small number of interdisciplinary journals, some of which are the most highly cited of all journals (Nature, Science); others have impact factors comparable to subject-specific journals (e.g., PLOS ONE, J. R. Soc. Interface, etc.).

If we discount arguments around open science and similar business model arguments (which could favor journals like PLOS ONE), and assume that the purpose of publishing is simply to get your research read (and cited) by the largest "relevant audience", when should one publish in an interdisciplinary journal versus a subject-specific journal (assuming they have comparable impact factors)? (Are there any papers out there that compare the fate of publications [or their authors!] in the two different types of journal?)

Thanks in advance.
My opinion on this is as follows. If your research advances the state of the art of field X, either by adding new knowledge specifically to X or improving existing methods/knowledge in X, you should submit to an X-specific journal. If your paper improves knowledge in field Y using methods from field X, I would either publish in a journal specific to Y, or in an Y,X interdisciplinary journal.