There is a lot of misconception about online programs but as long as they meet the same standards of accreditation that public universities meet, then you will get out of it what you put into it. Be sure the school is regionally accredited, be sure that if you are looking at getting licensed you check out the laws in your state. Pick a school that will meet that states licensure requirements.

A PhD is a degree that is a very individual degree and research intensive, I personally think it is the perfect degree for an online environment as long as you have access to your professors for questions.

I have attended both state universities and online universities and I can only tell from my experience that I have learned much more from my online program than I ever did at state university. I have written more research papers, done more homework, read more books and conducted more research than I ever did at NSU or UNF.

Like anything, research what is best for you and what your needs are. Do not listen to others about diploma mills. yes they exist, but if the school is RA, then they have met the same standards as RA state universities.

Good Luck!
References :
Institutional Accreditation
Argosy University is regionally accredited by the Higher Learning Commission and is a member of the North Central Association (NCA) (30 North LaSalle Street, Suite 2400, Chicago, IL 60602, 1.800.621.7440, http://www.ncahlc.org; 1-312-263-0456.

Accreditation by the Higher Learning Commission ensures that the online education you receive meets established standards of quality.

Walden University is listed in the U.S. Department of Education's comprehensive database of accredited post-secondary educational institutions. The database is searchable by institution name, accrediting body, and geographic region.

Walden University’s M.S. Degree in Nursing program is accredited by the Commission on Collegiate Nursing Education (CCNE), a national accrediting agency recognized by the U.S. Department of Education. CCNE ensures the quality and integrity of online degree programs. For students, accreditation signifies program innovation and continuous self-assessment. Graduates recognize that, as they seek new positions or entry into doctoral programs, accreditation is valued and may be required.

We’re proud to announce that Walden University’s M.S. in Mental Health Counseling program is now accredited by the Council for Accreditation of Counseling and Related Educational Programs (CACREP). Walden is one of the only schools that offers a CACREP-accredited M.S. degree in Mental Health Counseling online.

University of the Rockies® is regionally accredited by The Higher Learning Commission, a commission of the North Central Association of Colleges and Schools. Accreditation by the commission provides assurance to prospective students that the University of the Rockies has been found to meet the commission's stated requirements and criteria.

Online universities are wonderful for working professionals and busy parents, but PhD research just isn't well suited for it. Consider looking in to your local stat universities instead.
References :