Cheops-ng is a Network management tool for mapping and monitoring your network.
Differences between Cheops and Cheops-ng:
In cheops-ng the -ng stands for Next generation giving rise to a spinoff or newly developed version of cheops
Cheops is a GUI program whereas cheops-ng has a backend server that is running all of the time. The GUI for cheops-ng just loggs into the server to use the server's functions, like OS detection and mapping.
Cheops-ng's and Cheops' functionality only differ in that cheops-ng does not have monitoring capabilities yet.
Last but not least It is being worked on (ie. people are developing it and supporting it, whereas cheops is not being developed on nor supported).