MPLAB-X is very nice IDE based on NetBeans.
As microchip has stopped making further releases for old ide, we have to use the new one.
I am using this for my new projects and for old one i am still using my old ide.
All compilers which were supported in old ide is supported in new ide, we can say better support.
Coming to debugging part, pic kit 2 and pic kit 3 works directly but for high end debuggers like icd 2 icd3 and real ice you need to use mplab switcher, which is installed with ide installation.
In this you have to select which debugger you are going to use with which ide and then everything works properly.
They have put lots of efforts in this ide and is worth it.
Even you can import your existing old ide project in the new ide with single import click, it works for me always, may be it will create problem for others.
Still there are some issues with the ide, i get some errors when i build the code and that are not related to my project files, and after rebuilding everything works fine.
My suggestion for you, go with the new ide.