I'd start with stating that this keyboard has an amazing look & feel. The keys are exceptional and very pleasant to touch, the aftertouch feels just right. modwheel is solid and the touch stripe is unobtrusive and handy for a bunch of orchestral use cases. The screens allow you to do a good chunk of work without reaching for the mouse. The only hardware issue is that encoders are very close to each other so if you have big fingers you'll have to be careful.
Now, all the magic is contained within NI's own instruments. If you're a heavy used of Reaktor and Kontakt you'd feel at home. The keyboard has a few extra buttons for Maschine too but it doesn't come with a software so those would sit unused (which is sad given I'd love a few more buttons for ableton integration).
As soon as you leave the NI world ? e.g. to use your DAWs built-in instruments (NI is massive et al but I like my Ableton's synths) the keyboard changes. It still retains the basic DAW navigation features but now it's a VERY DUMB midi controller. No chords magic, no arp, everything is contained within the NI toolset (which is sad given how good the built-in arp is). You're left with eight encoders and the piano strip.
To sum it up: it's 10/10 for NIs toolset (unsurprisingly). The LED guide, the instrument picker ? everything is smooth and polished to let you focus on the music.
As soon as you're back to your DAW it's 6/10. It's not too bad ? e.g. you can do arp with ableton and you can load your other VSTs within the KK's tool so that they would avail of the extended feature set. It's just that the keyboard doesn't feel as capable anymore. Low-level Novation instruments would easily beat it in terms of raw midi capabilities.
Bottom line: worth the money if you are heavily investing into NI instruments too.