The handling of the APC 40 has been very poor in my experience. I use it with Ableton, especially for live performances. Mine seems to have a very bad glitch that causes some buttons to randomly stop working/responding.
For example, I've had the performance arm buttons stop working during a live performance several times. And these are not the only buttons that have suddenly stopped working.
Perhaps even more frustrating, these buttons usually start working again a few days later. I have done a lot of research on fixing this problem, especially checking midi configuration, but nothing has solved this problem.
In fact, after months of not using it, I took it out last week and the scene launch and master buttons were not responding (big surprise). Today, while working in Ableton, the solo buttons stopped working and I decided to write this review since I'm sick of the APC 40 not working properly.
I even sent the product back to Thomann, but they wouldn't replace it. I've had my friends try my APC with their computers and DAWs, but it still does not work properly. Very disappointing!