Perhaps the HP-42S was to be released as a replacement for the aging HP-41 series as it is designed to be compatible with all programs written for the HP-41.

The 42S, however, has a much smaller form factor than the 41, and features many more built-in functions, such as a matrix editor, complex number support, an equation solver, user-defined menus, and basic graphing capabilities (the 42S can draw graphs only by programs).

Additionally, it features a two-line dot matrix display, which made stack manipulation easier to understand.

[1] The HP-42S is keystroke-programmable, meaning that it can remember and later execute sequences of keystrokes to solve particular problems of interest to the user.

Important difference is that XEQ executes the label and returns to previous subroutine and continues execution from the line following XEQ,whereas GOTO branches to the label specified and doesn't return.