I have used the new build for a while, and let me say that I am very satisfied of being able to increase the font size.
I still have a list of problems of my own, but let me start with this one.
In Pan6 when one opens a cell, and does something else, the cell (or the Find/Select window or any other) closes automatically.
This is not the case anymore in PanX; I remember seing a discussion about that and I still wonder if this is a good solution.
Anyway, if I have a cell opened, and request a procedure through the action menu (before closing the cell) PanX crashes, and has to be forced to quit. I tried that on two different machines.