I bought this because I needed a midi controller to control my orchestral libraries(expression and dynamics)and it works great.
It has a bunch of different modes for different DAWs you choose them with a combination of the buttons.(the manual goes through this for almost every daw and if your daw is not on the list it has a "universal" mode)
In ableton the first three channels or the first two are pre mapped to the corresponding controls in the Korg Nano. To bypass this just map the controls that are already mapped to something else and then delete the new mapping you just made and they should be clean.
Pros:
The faders feel great
It has pause, stop, play, record buttons
Solo, mute ,rec for each channel separately so you don't even have to use your mouse when recording
Its used a lot by many djs/producers both live and in the studio
its built really well it feels solid
You can't beat the price!
Cons:
The only con that I can think of is the potentiometers feel a bit too easy to twist so be careful.
Overall a really good controller and all most of us are ever going to need. And with a great price!