Question: I was thinking to start Java enterprise development, so I started with Spring framework. I have already worked on some simple applications like CRUD apps and web services with STS(Spring Tool Suite). I know that there are lot more IDEs available like Myeclipse, intelliJ IDEA, Netbeans, Eclipse ee etc, and all of them have good support. However as a beginner, it is not possible to make a good comparison between all of these. But I have worked with Eclipse ee, therefore I find STS is better than eclipse ee, (I know sts is eclipse powered). Again, I heard from others that IntelliJ IDEA is the best. So I installed it, and got a lot of hiccups. Last day one of my friends suggested me to try Netbeans. So I need to know which IDE has better support like code generation, code assistance etc.

Answer: 
I haven't tried STS (<http://www.springsource.com/developer/sts>), but for Spring development I would guess that the IDE written by those that write Spring may have the best support.

But, if you are going to pick an IDE based on one technology you should be careful, otherwise you may find that you will need to use several IDEs in your development, eventually.

You may want to consider what other needs you want from your IDE, as, if you can have one that can meet all your demands then it may simplify your life.
The answer is that there is no answer. It comes down to personal preference, what you get used to or policies in work. 

Personally I like to know what is going on under the hood, so any old text editor might do, though I quite like STS Spring Roo support (though don't know what netbeans or intellij have to offer.