Coot is a molecular graphics application. Its primary focus is crystallographic macromolecular model-building and manipulation rather than representation i.e. more like Frodo than Rasmol. Having said that, Coot can work with small molecule (SHELXL) and electron microscopy data, be used for homology modelling, make passably pretty pictures and display NMR structures.
Coot is Free Software. You can give it away. If you don't like the way it behaves, you can fix it yourself.