Unfortunately for Netbeans zealots, it has never caught up with Eclipse. It may have surpassed it temporarily for certain apps (think Grails support - but look at STS 2.2.0). It's also not as good as IntelliJ IDEA (previously, always non-free).
Yes, both Netbeans and Eclipse are also RCP platforms, but how many real Netbeans platform apps are there? (The Nokia one on the web site is vapourware - yes it shows a real customer RAN - without their permission, I should add! - but it's never been a product delivered to customers). Real Eclipse RCP apps do exist (XMind, Lotus Smartsuite...). Realistically, they both over good RCP platforms (one pure Java, one SWT) but Oracle won't really care about that.
As for JDeveloper - well it's a typical Oracle product - if you're in an Oracle house, it's pretty good, but no, it's not got a large userbase or community supporting it.
Oracle should let Netbeans drift off into open source land. Perhaps it'll thrive? I don't know. JDeveloper's functionality should be ported to Eclipse (along with SQL Developer, while we're at it).
Oracle are great at giving you tools once you've signed up for the ride, and why not rebase your products on the best? Which in my opinion is Eclipse.