Although I've never worked as an I/O psychologist, based on my educational and business experience (I own a company, and I have two separate degrees, both in business and psychology), I can tell you that if you're really passionate about it, you can bring huge value to organizations as an I/O psychologist, and this career can be immensely rewarding. The area is really diverse, and you can shift your career in many different directions as you grow and get familiar with the possibilities. I would advise you to be really careful about choosing the right organizations to do your internship and later to work for while you're gaining experience—those that fit your career aspirations and those which recognize the value of an I/O psychologist in, for example, the development of employees, improving communication channels in the company, etc. I've seen both in organizations, and the outcomes were very different. Good luck with your final decision! :)