This is an excellent very user-friendly device that works across a multitude of applications. The arrangement of the buttons, knobs, and faders has been useful to me in audio, video/projection, and DMX lighting control. The one complaint I have, is that the buttons are a little difficult to depress, and could be a little shorter, with a little less motion required for activation(actually it's kinda nice if you're projecting on the fly, and you wanna make sure you don't accidentally call-up the wrong clip).
This is my main controller. The more I learn about programming within Ableton and Max for Live, the more powerful this controller becomes. I mainly use the 32 step sequencing abilities of the two bottom rows of 16 buttons, and use the 8 faders, topped with three knobs over each fader performing within Ableton's clip-launch mode. The center section I tend to use for clip launching loops over the sequencing, unless I am using it for a drum rack. The 16 push encoders located top-center are invaluable when utilizing effect chains, automation, VST and effect manipulation... and in truth, none of this should be taken as permanent. I constantly change the functions of a lot of the controller because it is so versatile. I haven't delved past the very beginnings of what the CNTRL:R can do WITHOUT a PC. I've used it with my Dave Smith Mopho Desktop and a keyboard controller via straight 5 pin MIDI and was blown away for the short time I was just exploring the additional capabilities. And not that I know HOW to do this, but I know it can be a powerful Traktor controller, and for someone who knew what they were doing, this thing can even control performance LIGHTING via MIDI. It will take me years to learn and be able to confidently use all of the CNTRL:R features. For now, I love it as my Ableton centerpiece. I have added a Livid module via the available ribbon cable expansion jack. There are several models but I chose the XPC 4K2JS (4 Knob, 2 Joystick) The XPS modules are in rugged aluminum boxes and all have specialized additional controls. The "Joysticks" are especially useful in navigating around in device chains in Ableton. I have also added the Livid "Master Fader," a crossfader plugged into the CNTRL:R via 1/4" cable - into one of the two 1/4" jacks on the CNTRL:R. The other jack can be used to run a pedal- very useful for looping within Ableton while using both hands manipulating devices, effects, or other external gear. The Livid Instruments CNTRL:R continues to be my ideal Abelton MIDI controlling tool. It is a shame they have stopped production of CNTRL:R.