I like that it's a great resource to find and download BIM/Revit families for MEP manufacturer specific elements. I don't use it that often though because the elements available are mostly European and I'm in the United States. Review collected by and hosted on G2.com.

It seems that the majority of the components are for manufacturers outside of the United States and there's not that many available through the site and/or the Revit plug-in. I tend to use BIM Object more often because they have a large library of components to download into my projects also, many of them are available in the U.S. Review collected by and hosted on G2.com.