Not sure why it wouldn't be a popular topic. Kontakt is the #1 sampler, and probably accounts for 1/2 of all software instruments anyone ever uses. The Komplete package is SOLID, Massive is my Go-To synth. I've never even touched the Arturia V collection besides the Prophet and Oberheim VIs. I use my KeyLab88 with mostly NI stuff, as I've had Komplete for years, and it makes up the cornerstone of my VIs. Though I also use instruments from Korg, Arturia, G-Force, Roli and many others. A keyboard controller that's built for a particular piece of software is a mistake, IMO. And that's why I love the Keylab, and think the NI Komplete Kontrol is a bad idea. The Keylab is a generic controller, all it's controls are CC MIDI outputs, you can use them with any piece of software. It's not designed for any Arturia-specfic software in mind, though it interfaces just fine with it, and you may get some pre-mapping percs. The Komplete Kontrol, on the other hand, all it's bells & whistles (like the lights) are specific to NIs proprietary software. You can use the board with anything, but a lot of the selling-point features will be crippled. As much as I love NI instruments, I don't use them all the time, and I run all of this under Apple MainStage, of which NI Komplete Kontrol has no interfacing with, beyond it's basic midi features. As I see it, when you compare the Keylab to the KK side-by-side, if you remove all of the KKs proprietary features, the Keylab wins hands down, and is cheaper. I have no first-hand experience with the KK, though, so there could be something about it that blows me away. Maybe the keybed is amazing, but I suspect it's just another Fatar like the Keylab, Kurzweil, and the rest.
Hope that helps.
