Based on the criteria in your first post Ross, I would go with the ezone xi. If you are after build quality, pop spin and most of all good feel, I would take this one. I know you like full beds of shaped poly in the low 50s, thats perfect for this frame, power level almost identical to the apd, insane stability, more pop on serve etc...you dont have to customize.
I saw vandeweghe play serena live with this frame, coco was hitting bigger...
The formula 100 is nothing special, dodgy qc, if you have an old pd with silicone in the handle thats exactly what it is.
Linger on your pale blue eyes