MSW vs PsyD in Social Work
The question of which degree would best serve your career purposes, MSW or PsyD, depends upon your career goals. Presumably the reason you're considering this choice is your interest in counseling. That is the field the degrees have in common; a clinical MSW is meant for people who want to take on a counseling role, with individuals or groups. A PsyD (or a PhD) in psychology is the degree that clinical psychologists obtain for the purposes of working as therapists.
The PsyD Academic Commitment
The PsyD degree was developed in the 1970s as a doctoral level program in psychology that focuses on clinical counseling and therapy, and psychological testing. Traditionally the PhD in psychology has been a program to train top level researchers and college level professors in psychology. Like the PhD in Psychology, the PsyD (or Doctor of Psychology) requires completion of a dissertation and an internship. It can take 4-7 years to get through, depending upon how long you take to complete the dissertation; the internship obligation is two years - one of which must be completed after all other degree requirements have been met. All clinical PsyD candidates must pass the national Examination for Professional Practice of Psychology (EPPP).
The MSW Academic Commitment
In many states a true counseling license with a social work degree is going to require status as a licensed clinical social worker (LCSW) which generally will in turn, require two years of supervised counseling work (4,000 hours) to be completed after obtaining the degree. That's a long internship, but most MSWs get paid while going through it, or most of it, so it isn't like continuing the degree program. So obtaining a counseling license that covers all types of therapy requires more work than just the two years devoted to the MSW. For licensure the clinical MSW must also pass the LCSW exam, which may be a state exam or may be the national version developed by the Association of Social Work Boards.
The Differences in Career
So both degrees require some academic tenacity. The advantage of a LCSW is that the entire range of social service counseling jobs is open to you. Working with families in distress, in child intervention situations, providing mental health support in a medical or social service setting - all of these options are open to a LCSW. Social work and social workers cover a lot of professional roles, and the LCSW is one of the two premier licenses in the field.
A PsyD graduate will be licensed by any state to open a clinical practice, and many do. Generally speaking a PsyD can make more money than someone working in a social services setting. However many LCSW graduates find themselves providing the counseling in mental health settings while the testing falls to the PsyD graduates who are more qualified in that area.
A licensed clinical social worker is going to qualify for many more types of jobs in human services than a PsyD graduate might. However a Doctor of Psychology probably draws the higher level of respect - and a higher income - working as a clinical therapist. If that is your goal, investing in the doctorate might be worthwhile. If helping people in a social services setting, the LCSW is going to immediately qualify you for a wider variety of employment options.