Ranked in these QuestionsQuestion Ranking
Pro Ed is the standard text editor
As the standard text editor, Ed is available on multiple systems.
Pro Consistent UI
Ed has a consistent user interface and error reportage.
Con Not a lot of features
While extremely fast and simple, Ed is simply not for programming for a long time because it lacks a lot of important features. It should be used instead for quick edits.
There's absolutely no need for Sd when you have sed and ex.
Con Not a persistent UI
You can only view portions of a file through search or regular expression commands. You cannot scan or scroll through a file using the available screen real-estate.
It's not too dissimilar in use to command-line tools (such as grep and sed) for editing a file. In fact, both grep and sed are based on how interaction is performed with Ed.