I've used both. I have a personally bought copy of IntelliJ, though I'm using Eclipse now.
For the most part, they're both comparable. Both have powerful refactoring and code-generation abilities.
For core Java development, there's no need to leave Eclipse. IntelliJ might provide some nice features, but overall it doesn't warrant purchasing a license.
When combined with web development, other languages, or non-core development, is where it easily pays off to switch to IntelliJ.
We were doing some Grails work, and Eclipe's support (via STS) was shady at best. We put off trying IntelliJ since it meant learning a new environment, new shortcuts, etc, but after about a day of playing with it, we were sold, and never looked back.
IntelliJ is also a lot nicer for Scala than the Eclipse plugins. The Python plugin is pretty excellent too; it brings in most (all?) of what you'd buy PyCharm for.
For the most part, they're both comparable. Both have powerful refactoring and code-generation abilities.
For core Java development, there's no need to leave Eclipse. IntelliJ might provide some nice features, but overall it doesn't warrant purchasing a license.
When combined with web development, other languages, or non-core development, is where it easily pays off to switch to IntelliJ.
We were doing some Grails work, and Eclipe's support (via STS) was shady at best. We put off trying IntelliJ since it meant learning a new environment, new shortcuts, etc, but after about a day of playing with it, we were sold, and never looked back.