Native Instruments Komplete Kontrol S61 by Groovizm
This is no in depth review of all functionality. Please head over to the Sound on Sound website for that kind of review. This is just my personal opinion, based on my own experiences. I hope this is useful to you.
Before we start it is important to note that the Komplete Kontrol Keyboards are the hardware controllers for the Komplete Kontrol software. Without the Komplete Kontrol software, the keyboards work in stand alone mode. You can still use them as midi controllers, but the functionality is greatly reduced. The light guide, scales, chords and arpeggiator do not work in standalone mode.
I bought the S61 mainly to unlock the full potential of Komplete 11, which I already owned and which, I think, sounds great.
The S61 has some great features; the way you browse the library form the keyboard is great. Depending on which instrument you have loaded it is also very easy to tweak the sound. The rule here tends to be: the simpler the synth, the greater the "tweakabillity". It has become so much easier to find sounds and to tweak them, that Komplete has absolutely doubled in value for me.
The integration with the DAW, Ableton Live 9 in my case is limited. Play, Record, and Start/Stop work fine, as does switching the loop on and Off. Other functions that are mentioned in the manual do not work and I did not get a really clear reply from Native Instruments why this is. They seem to admit that that it is partly a bug and that things should be working with Live 10.
The light guide is no use to me, and neither are the scale and chord functions. The arpeggiator is great, but, as explained before, these functions are all depending on the software, so in stand-alone mode these functions do not work.
The hardware is very good, though. The keys play very nicely. The buttons and encoders feel great and the screens are easy to read. It all looks and feels very classy.
Bang for buck
I bought this for 300 euro on the second hand market and I'm happy with what I got. However, a new MK2 is ~ 650 euro. In that price range there's a lot of alternatives.
Personally I find hardware (step) sequencers very inspiring so especially the Novation 61SL MkIII which is a completely hardware based solution with 8 polyphonic sequencers on board might be worth checking out.