Nikon will be sending you a check for calling their software "very efficient". And for stating that their software is "easy to use", in a public forum no less (!), Nikon will be shipping you a new Nikon D4 body and 70-200 VRII lens.
Ummm...if you shoot very small batches of images, and have the patience of Job, and just wish to pull out and work on two or three selects from each shoot, Nikon Capture does give good results. And unlike Lightroom or ACR, NX2 can actually read the encrypted white balance on each and every .NEF file. No 'guessing', as the Adobe programs are forced to do, so the White Balance will at least be accurately represented on every NX2 image.
If NX 2 is stable on your computer, and it runs okay for you, then you might wish to buy it and use it. Different people have different needs; Nikon's software does have some neat features. I would say LEARN what it can offer. It is not an Adobe product, and it offers Control Point editing, a lot like Viveza offers, so that's cool. And the lightness channel is nifty too. And non-destructive editing of raw images. And some other stuff. If this represents your first-ever raw image processing software, you have no 'habits' to un-learn, so hey...use it for 60 days, and see what you find out. See if it crashes if you try and batch 100 pictures from raw to JPEG. And so on.