The simplicity of the test editor is its USP. It does only those things that it is supposed to do. I use it heavily for doc comparisons and doc editing.

Advanced text editor with built in syntax highlighting, markup preview, great diff tool including ability to diff folders not just files, open remote folder via ftp/sftp, search and replace with grep capability, sorting, duplicate line processing, ability to open file or folder from command line, and many other features.

It's stable, always "just works" and it not cluttered with unnecessary buttons.