<p>Well to address the question no one has touched, deciding whether you want to get a Ph.D. or stop at M.S. depends on what kind of job you are looking for. You can get into research with both, but if you want to be running research programs you will likely need a Ph.D. The other thing to consider is that if you get a Ph.D., you are qualified to run a research program, but not a whole lot else in the eyes of industry. You really close a lot of doors, so you have to know that research is what you want before jumping into a doctorate.</p>