It should be possible to allow an updating mechanism for getting from one Netbeans release to another. For example, I have 7.0.1 installed as I want. How do I upgrade to 7.1? Download it again? Did I download the Java SE version before, the Java EE version or the "All" version? I can't remember - and I shouldn't have to. Also, I'm not sure if the old version will be removed for me and my preferences / projects transferred - as an end user I should have confidence that nothing will be lost.
At the very least, it should be possible to upgrade from beta to RC to stable. It's annoying to uninstall/install each version three times for each version. It also means you're not getting feedback, because people (like me) tend to skip some builds altogether.