So I decided to try out IntelliJ Ultimate based on a colleague's recommendation. Overall, I've been happy with the experience. It is very stable (I've only had one crash since I've been using it, and I was running a lot on my system at once). Deploying to Tomcat servers has been a breeze.
It's not without its quirks though. For example, things that just work in Eclipse, such as auto-wrapping long comment lines, don't work in IntelliJ. I've also found that the gradle support is still new and can be buggy at times (especially with auto-synchronizing Intelli's dependencies with the gradle build's dependencies - though I've heard that's in the works).
What I've been most impressed with is the support. Whether on the Jetbrains forums, bug tracker or stack overflow, the IntelliJ support team generally responds very quickly to posts.
Overall, it has been a pleasant experience. If you're fed up with Eclipse, I recommend giving IntelliJ a try.