Okey now i tested the windows 7 x64 and i would say 4.5/5, most works right except some dialogs (for example creating a new project) begins as a black screen and slowly paints itself.
fortunately jdk 11 downloaded from the b4j page works with UI app and the packager works, but the packaged file does not lol ?
so far i am impressed that we are able to run wpf projects in linux and the jdk too, this was impossible 2 years ago.