Harold - since we went to an external router with the X18 and connecting using the 5G band then connection to the mixer has been rock solid.

The mixer itself has been excellent. Very occasionally doesnt boot up properly and you have to turn off and on again. Only niggle is that it doesn't have a discrete effect on/off footswitch. Trying to accurately hit the echo mute on a touchscreen sometimes demonstrates that touchscreen interfaces are not quite so effective if you just make a quick jab at the "button".

Being able to wander around a venue and tweak the sound instantly is really good.

I'm not sure that the free Behringer software is available for an iPhone. I think there is a 3rd party paid-for app that does this.