In my experience with NI kit, it's great if it works. If it does not, you have a heck of
a job getting through to a tech support person.
I've had / have Kore 2,
Maschine, Guitar rig with the hardware bit and also Komplete. No major issues. I bought
the Komplete audio interface and had several weeks of complete frustration. In the end, I
returned it and got a Focusrite interface. Raising a ticket with NI support and then
waiting days then emailing them again then getting ignored. When they do respond, it is
typically to send you a copy of the FAQ which you've already explained that you've read
and done. Repeat to fade.
All of the above was on a system that is using the
official drivers for Windows 7 - if they don't seem keen to help a very regular customer
who is using the 'correct' drivers, I don't fancy your chances if you have any issues on
XP as they'll just blame you

It's a real shame as those who have no issues with this interface (which seems to be
almost everyone) seem to love it so I'm sure it's good with the above 'if it works for you
and if it doesn't you're on your own' caveat.