[funcDropShadow]

> but it looks like vim really has undo/redo "solved"

Does it support restricting undo/redo to a selection? In Emacs you can select any region of text and just apply the undo history of the selection. That is extremely useful. Imagine working on to functions in the same file. You have are working on g() and realize you want to undo some change on f(), that you did before. Most editors don't support that. In Emacs you can just select the code of f() and press undo (C-_).

Several popular undo extension libraries break this feature.