DSpace is the more common of the two in our index: it runs on 9 websites against 3 for Data8. Counts come from real scans of each site's home page, not vendor claims, and cover the sites in TechLookup's index rather than the whole web.
DSpace is a software platform for academic, non-profit, and commercial organizations to create and manage open digital repositories.
Within the dms sites we have indexed, Data8 holds 5.8% and DSpace 17%.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.