[vram22]

The Norton Editor (NE) was very good too. Really fast. Probably written in assembly, maybe by Peter Norton himself. I had bought and read a book of his on programming in assembly language (x86) for the IBM PC. Also very good. He developed a TUI hex editor in the book as a running case study, IIRC.

Also the Norton Guides were fantastic. TSRs [1], but with a TUI. You could get guides for C, dBASE, Clipper, Assembly, etc. I loved the TSR popup experience on DOS.

[1] Terminate and Stay Resident programs. They hooked into a keyboard interrupt to allow them to pop on a press of a hotkey.