When comparing Codename One vs Fuse, the Slant community recommends Codename One for most people. In the question“What are the best frameworks for developing cross-platform mobile apps?” Codename One is ranked 5th while Fuse is ranked 7th.
Ranked in these QuestionsQuestion Ranking
Pro High performance
Pro Open source
Pro Highly customizable
By utilizing lightweight component architecture and the built in graphical designer and theming options you are able to customize a good looking app on any platform.
Pro Java 8 support
Pro Works with all IDEs
Works with NetBeans, Eclipse, IntelliJ, etc.
Pro Multi-platform development environments (via build server)
You can even use Linux desktops to build native iOS apps, no need for a Mac.
Pro Vibrant & helpful community
Pro Attractive pricing
It is possible to build production grade apps even with the free version. Pricing is decent when compared to competitors like Xamarin.
Pro Compiles to native platform code
A key difference is that Fuse uses JS exclusively for app logic while producing native code for everything else, including population and manipulation of the UI.
Pro Native performance
Pro OpenGL UI
With the option to use OpenGL based UI components, Fuse is the only of the three platforms that offer a reliable “write once, run everywhere” approach where designers can control responsive layout, look and feel down to points, pixels and percentages, keyframes and easing curves.
Con Little reuse of web knowledge
Fuse doesn't support Angular or React so there is little reuse of existing web tech knowledge. The team have said they are exploring Angular 2 and then maybe React though.