Both programs are write for gamepads - probable in the last decade no one write freeware program for joystick, exception perhaps of Newview.* But both program work fine for josytick.
Xpadder (9,99$) have more
advanced functions that JoyToKey, but you need more than JoyToKey do?
The only function missing for me is "mapped key on press" and "mapped key on release" on same (toggle) switch.
I like JoyToKey because they are simple to configure/use, allow start after game, reconfigure "on the fly"...
*
Newview is joystick software write for Il-2 that allow "emulate" TrackIR with POV HAT.
Is keymapper too with advanced functions. The only downsize is the lack of support in English, since the author are Russian, however provide English GUI.
EDIT - Since today joystick definition varies for many people, for "joystick" I refer to this
kind.
Sokol1