Personally I have no need for drag and drop GUIs as all my GUIs consist of handcoded HTML in the form of JSPs and XHTML with copious amounts of CSS
I can see where for people working on Swing GUIs Netbeans could have an advantage though any visual environment invites sloppy separation of display and business logic (just double click the button in the editor to add the code for the business logic that goes under it, we've all done it at some point...).
Therefore GUI editors need to be used with extreme caution and self discipline!