Updating this review, as I've owned it for a while now. I'm still happy with this purchase, about 2 months after buying this.
You have so much control over various softsynths (courtesy of the Komplete Kontrol software), way more than you'd generally get with MIDI controllers. You can not only browse for sounds and select one without touching the mouse or keyboard, but also edit the sounds as a whole.
The small size and profile of this controller is a double-edged sword for me. It's genuinely nice that I can fit it on my table, but I wish I had more keys. I love the idea of touch strips for the wheel controllers, but can't help but feel they could've been executed better. LEDs, maybe? Simple prints showing several zones of interest (like middle for pitch wheels)? Maybe even something like Arturia's doing with their Minilab?
The keys feel nice. I'm no keyboard player, but I did genuinely feel a difference between my old Keystation and this. I have more control over the velocity range (though because the keys are lighter on the Komplete it doesn't end up being that big of a deal), the keys feel far less spongy too.
It's made a difference to me that I don't know if it's worth putting here, but having it be available whenever I need it right in front of me makes it much better for me to stay 'in the loop' and actually play better as a result too. My old setup had me spinning back and forth between keyboard, laptop, keyboard, laptop, and so on...