The Z Flip seems to fold closed a little more cleanly than the Fold did. In other words: there's less of a gap around the hinge between the two folding halves.

Open the Z Flip up, and you'll immediately spot the crease in the display. That new glass sure creases like plastic...

Looks like it scratches like plastic, too! Unsurprisingly, it's not as durable as the Gorilla Glass that adorns the non-folding devices we're used to.