Netbeans team made one very good decision way back that IntelliJ still comes nowehere near to competing with: Integration with the underlying build system (Ant/Mvn/Gradle). IJ frequently gets itself into some weird state where it becomes uncoupled (unhinged?) from the Maven POM and has to be manually synchronised. Netbeans essentially does not have any independent notion of dependencies or build system, so there's never a sync question.

This also means that NB is infinitely better at handling/managing Maven sub-projects/modules, where IJ is pretty much always lost and blundering about in the wilderness.

All that said, I do believe that the Netbeans project has more-or-less lost the plot. They're spending so much time and energy trying to provide a language-server thing for VSCode that their own project is falling further and further behind the curve.

Try the (free, or premium) tabnine plugin. It uses a ML model to analyze your codebase for patterns and suggest better-and-better autocompletion over time as your project grows--it works really seamlessly with the IntelliJ autocomplete--so, it only adjusts the suggestion list when there isn't a straightforward suggestion from IntelliJ's already.

NetBeans’ auto-complete, in particular method call argument auto fill-in, is an important reason why it’s still my primary IDE for Java development.

It’s also slightly easier to (almost) fully keyboard-operate than IntelliJ, in my opinion.

Another thing I like is that Netbeans can open and work with Maven projects without having to “import” them.