I'm using a Quneo of Keith McMillen and it's pretty awesome.
Though you need to use a usb-power/control splitter cable to power the quneo externally as the LEDs draw quite some current and will create quite a noise on the output if you power it from the axoloti.
That said, I'm pretty fond off the controller as it's also able to receive midi-data and show it on any of the pads/sliders/buttons. For example, my quneo-sequencer sends it's sequence-data to the quneo when switching between channels/loading new sequences, allowing me to see and edit the sequence. Or, another nice one: show the vu-meter data on the audio-output on one of the sliders,
The pads are wonderful, as these not only send gate,note and velocity, but also aftertouch and X/Y controls for each pad (and even continous aftertouch on all buttons and sliders!).