The following chart compares some relevant features of three text engines for the Macintosh: TextEdit (the original text engine built in every Macintosh), MLTE and WASTE 2.1.

Some features require some explanations:

This table summarizes the main features supported by TextEdit, MLTE and WASTE 2.1.
  TextEdit MLTE WASTE 2.1
Underlying Rendering Layer QuickDraw Text ATSUI QuickDraw Text
Minimum System Requirement 6.0.5 9.0 7.1
68K Support  
Carbon Support
>32K text  
Double-byte Script Support
Bidirectional Script Support
Inline Input ✓ (with TSMTE)
Character-Level Formatting (Styles)
Paragraph-Level Formatting (Rulers)    
Full Justification  
Drag & Drop Editing  
Embedded Objects  
Unicode Support