I was planning a panel incorporating a mounted iPad mini. I have been using iPads (mini and 9.7" full size) as EFBs since they first came out. I have had them "loose" and yoke mounted and found them perfectly useable.
Recently I been flying an airplane with an iPad panel mount. Glad I had the opportunity, I found out I hate it that way. I found it frustratingly unstable to operate, nothing like my previous experience. Rarely did my first touch give me what I intended. The amount of time it took away from my piloting was inordinate. I suspect the major factor in my lack of satisfactory operation is the vertical mounting position of the unit.
I have used many other touch screen avionics systems. I'm not sure who thought a touch screen interface was a good idea in a moving vehicle, but unless the ride was smooth as glass, using them is a major time-sink, far more than I deem acceptable for safe, aircraft operation.
This is just one mans opinion. YMMV.
George