I have been using it a little bit. I still have 17 days to go on the
trial period. You can download a 30 day free trial version at
www.nikonusa.com.

It is completely different from Capture. The whole interface and look
and feel are different. Some of the tools are very powerful. In
particular I like the distortion control. And Nikon still knows how to
get the best color and exposure out of a RAW file. The noise reduction
is pretty good, too.

You could do most of your editing in NX. I still have not found a dust
or speck remover tool, but otherwise the program is a pretty good
editor in its own right.

It appears that the program is still using the idiotic protection
scheme notorious for its tendency to crash operating systems, both
Windows and OS X.

Been using it for a couple of weeks with a mixed outcome.
Some bits are very good - RAW conversion excellent, interface much better
than Capture.
Had some speed issues at first but it now runs a little faster than Capture
does.

BUT...  I just downloaded the beta of Adobe Lightroom and find it
excellent - I'm no Adobe fan (slow bloatware) but Lightroom really fits my
workflow - used it on 170 pics from a shoot this w/e and found it intuitive
+ fast to get what I wanted. Project handling is good, RAW conversion (D70)
excellent...
http://labs.adobe.com/technologies/lightroom/?trackingid=IFQT

Well worth trying the beta demo...

Guy

I kind of like NX, and will likely buy it, but it is not a Photoshop
replacement.
The control point system in NX is a clever idea and for some images it can
be faster to get to a desired result than using Photoshop.
I can see how Lightroom is useful for making simple global tweaks to a
collection of similarly created images but it is not intended as a Photoshop
replacement--Adobe has left those controls out of Lightroom on purpose. I am
not exactly sure what Adobe is trying to achieve with Lightroom,  as much of
it seems just an alternate interface to Bridge and could take the place of
Bridge in the next version of Photoshop.
Bibble, Lightroom, Raw Shooter, DxO are quite similar in the controls they
offer over image manipulation and in results in my experience. It is a
matter of personal preference whether these converters are superior to the
Adobe converter. There is a reason that all these converters are set up to
link to Photoshop for final image processing.
Once a raw image is opened if you use 16 bit color, for those who believe in
the superiority of greater than 8 bit color, there is no technical
difference in working on the image in Photoshop with its many tools,
including the ability to selectively alter parts of the image, or the
limited tools of a raw converter which applies global alterations to the
image. If Adobe makes the next version of Photoshop fully 16 bit compatible
there will not be a reason other than preference for manipulating an image
in any raw converter, if there is one now.
For my non-professional purposes I have few images that are ready to print
straight out of a raw converter without a few finishing tweaks in Photoshop.
Doubtless this reflects a defect in the technical quality of my images but
my experience tells me this is the case for the majority of photographic
images, particularly those created on digital sensors with their limited
dynamic range.
There ain't no such thing as a straight print of an Ansel Adams negative
either.