I'm a long time user of Eclipse but recently have tried IntelliJ again, it's got some really nice features such as the inline values while debugging but by far the biggest annoyance is not being able to have multiple projects within a workspace.

At work I mainly work on two APIs that work closely together so in Eclipse I can have both open and just jump between the projects easily and at home I like to have all my scratch pad projects/ideas in one eclipse workspace so I can jump between them all easily.

I know there are kinda workarounds with modules but it doesn't really work well, if they allowed the ability for multiple projects in a workspace I'd jump ship but sadly it seems it'll never be supported (according to co-worker who is a die hard IDEA fan).