I'm using Intellij now, but used to work with Eclipse. And one thing that I miss is quickly starting tests. In Eclipse it feels like tests start without compilation and I get instant feedback. With IDEA you have to wait a second or two before it starts running the tests. I know it doesn't feel like much, but it's really annoying if you are doing TDD.

I started using IDEA because I wanted dark theme and Eclipse didn't have it. Probably even now you can't get nice looking dark theme in Eclipse, not sure, correct if I'm wrong.