This is exactly my same experience almost word for word. Brought the Fly Z out yesterday for a field test outdoors, just not an indoor monitor guy. If I can't see and feel the entire ball flight, then I've learned not to buy.
Put the Fly Z up against the 2017 M2, the 565, Epic SZ and the F7+. Stock stiff shafts and configurations.
Swing speed in the 95-105 range and what was funny was the Most Wanted Chart by swing speed was almost spot on:)
The M2 topped my list in almost a tie with the F7+. The Epic SZ and 565 about 5-10 yards behind over about a 100 ball average, 20 balls with each club.
The Fly Z was right there with the M2/F7+ and really no negligible difference. The F7+ could be fun with Cobra Connect but no huge difference over the Fly Z other than maybe a little softer off the face than the Fly Z....
I'm going to take another stab over the weekend and try and put the regular Epic in the mix.
As you said it's hard to find a bad driver these days and you could probably drop a blanket over all of the results at the end of the driving range.