The main gripe with Netbeans is that it is slow. Compiling is fast enough but that does not make up for everything else being so slow. It takes ages and ages for the code completion popup to appear and then continuing to type while it's open is painfull. Even without the code completion dialog, you feel that the text appears on the screen much slower than you type it. It may be percieved but perception matters a lot when it comes to software usability.
Sure Netbeans fans will argue that it is a hell of a lot faster than eclipse. There is no denying that fact. Being faster than eclipse does not mean fast.
Another gripe is with the macros, who can keep all those macros in his head? and woe betide you if you unwittingly choose to assign a macro code as a variable name.
Whenever you choose to 'find usages' of a variable a dialog pops up asking if you want to search in the comments. If you have commented out large sections of your code, that means you are not a good programmer. You should learn to use a version control system instead. Having this dialog which I have never used and which I never plan to use means I have to move my mouse again. I have a sore shoulder.
Last but not least I don't like this business of having a 'Main Project' sometimes you compile dozens of times pulling at your hair wondering why the code changes are not been executed only to find that it's compiling the main project instead of what you want it to compile.
So what's my verdict?
Netbeans is a wonderfull IDE. It just needs to sort out a few glitches.