<< i think the Design is good, because you can put more features/functions in a square menue than in a circular, imho.
But absolutly not "ergonomic" ! :)
<< you can put more features/functions
Not a problem : just multiply Pies!
See Blender Menu Pies : it's runing 10 times more speed!
And some tricky uses of parameters inside! Absolutly amazing!:)
You can have all principal functions under fingers!
Sure you must config first (or load some yet made) but after what a confort!
You have not that with the very rustic rectangular box of ZBrush! It's a nightmare to use the ZModeler! :)
Maybe in the ZB 5.0 !
here a Pie specialized in Sculpting : Pies menu is the more adapted for numerous functions!