Plone have a great history with online forms. PFG works really well for creating online forms and editing them through the web. PFG is based mainly on archetype content type. So the project mainly focuses on improving the collective.easyforms (forms for plone with dexterity content types) to make it compatible to work for Plone 5 and provide full test coverage and improve the tests. Also the feature to convert the content type of forms from archetype to dexterity.