Aspen University is not a diploma mill school and they are accredited but they really don't have the best accreditation. The best accreditation for any university is Regional accreditation.
I don’t know what future employers will think about Aspen. It depends on if you live in Colorado or plan to get a job there. I work for a very small university but everyone on the East coast knows about this university and we have a good reputation. Will your future employers know about the school?
You might want to consider Regis University’s online MBA program. Regis University is regionally accredited by the North Central Association of Colleges and Schools. Regis University has a very good MBA program that is online.
Online MBA Program - Marketing, Accounting & Health Care Management :: Regis University
If you have any other questions let me know. I work in Higher Education so I know the business.