depends on what you are looking for - I personally like eclipse more but the IDE itself is not that well polished and the debugger still has some bugs.
net beans is more polished and seems to have a better quality control process.
The other point is the GUI designer - the VE for eclipse is not as strong as NB GUI layout (people swear by it). Then again NB has no support for SWT.
Eclipse is strong because it has plugins - that will extend the ide to do a lot of cool stuff - database exploration,strong web app and misc. application server support -
Jboss has its own plug in which is very stable. NB looses out there.
I use eclipse not only for java but also for perl and PHP - althought the plug ins are buggy.
What I like most about eclipse is the coding - its got a very good editor. Java comments, automatic code fillers and also code formatting is quick and addictive - I cant use anything but eclipse now.