I generally use a Midas MR18 as an interface and mixer
A Behringer X-touch mini has 16 assignable buttons, 8 assignable lit knobs and an assignable fader
The X-touch lower row of buttons can be assigned to various QLab controls, Play, Pause, Panic, etc etc
then if I have spot cues they go onto next row of buttons
I generally assign the fader to a DCA and assign that to all eight of the MR18s outputs, like a live-level override
the Knobs are also each usually assigned to MR18 outputs but sometimes to a live mic channel or similar
-when assigned to a live mic channel when qlab fires a level change the Knobs LED ladder echos this, if you change the knob it will be from the current level, no matching required
you can even do the whole thing again on a 2nd page in the X-touch
The only really irritating thing is you have to find a PC to program the X-Touch mini! (non-mac, sigh)
-I tend to use the one pre-set changing other controls only occasionally, but I have never been not able to borrow a PC and edit within the hour
midi & power connection is via USB to your Mac