The RAND editor wasn't free. We had a site license for it at an aerospace company, so it was on all the UNIX systems. It was not used widely outside aerospace and DoD. "vi" was an attempt to do roughly the same job without the special hardware.
[1] http://www.rand.org/pubs/notes/N2239-1.html [2] http://terminals-wiki.org/wiki/index.php/HP_2645A