Is IntelliJ Community Edition vs Ultimate?
This purely depends on your requirement. IntelliJ (Community Edition) is free for use and is best suited for open-source projects. Also, it is predominantly used for JVM development.
Java developers can leverage the features offered by IntelliJ IDEA (Community Edition) for test development using TestNG, JUnit, and other test automation frameworks supported by Java. I have been using the community edition of IntelliJ IDEA and it works like a charm.
On the other hand, the paid IntelliJ IDEA Ultimate is primarily used for full-stack and enterprise development. The major reason is that the Ultimate edition supports a number of backend and frontend frameworks and technologies. You can find more information about the comparison here.