I've used a number of Java IDE's out there. JBuilder, Forte, Visual Café. None of the mentioned above has helped me out in programming as IDEA has. It is user and programming focused. The IDE performs no magic to your code such as special annotation or force you into some specialized way of notation or solutions, it simply helps you write your code in a simple and _most_ powerful way.
It is simple to install and quickly (as well as simply) setups a new project. First time I used it I set up our companys (big) project in 2 minutes with no hesitation or problem.
I use the evaluation version at home for minor personal projects and it by far the best IDE for minor projects as well.
The demo version is trouble free. It is some files to unzip and the uninstall is just as simple, just delete the files (no registry alterations) as it is a java application.
I believe you would make a big mistake not to try this program out, either you are a private person or a professional programmer.