How to effectively merge two directories in Emacs?

Question

I've tried to use plain ediff-directories to make a diff between files but this is very slow because I need to compare files on every nesting level and there are too many of them.

I've also tried ediff-trees (defined in ediff-trees.el) but that is not convenient either because I don't even see how many files are different and cannot see the picture in general.

Is there another way to do this?

Answer 1

The package https://github.com/fourier/ztree works nicely for this. Even works over TRAMP.