USGS
Equator offers Free Trial, but 21stCenturyGIS does not.
Equator is designed for Large Enterprises, Medium Business and Small Business.
21stCenturyGIS is designed for Large Enterprises, Medium Business and Small Business.
The starting price of Equator begins at $30/User/Month, while pricing details for 21stCenturyGIS are unavailable.
Some top alternatives to Equator includes eSpatial, ArcGIS Online, Map Business Online, vMAP, 21stCenturyGIS, 3-GIS, Agile GIS, ArcGIS Instant Apps and Geoconcept GIS.
Some top alternatives to 21stCenturyGIS includes CARTO, eSpatial, ArcGIS Online, Mapbox, 3-GIS, LandScape GIS, Urban SDK, Agile GIS, Geograma and Geoconcept GIS.