The Happs Optical Rotaries spin about as easily as a NON-rotary spinning joystick...that is, it takes some effort. mine aren't loose and free-spinning, although I'm sure there is a nut or some fixture inside thats making the compression extra tight.
The only dis-advantage is that you've got this large piece of "encoder and bracket" hanging off the end of your joystick inside the CP.....I would somewhat consider that encoder getting slapped around like crazy in your average fighter, perhaps coming lose. The feel of the stick is stiffer than a competition or whatever, but I dont think I'd want it as a stick for fighters.
Consider this: If you really only want a 2 player CP, add an extra spinner joystick (or two) to the CP and wire them both into your interface's inputs for joystick 1 U/D/L/R. This way you can choose which stick you want to use but MAME will see them both as Player 1 stick, etc.
....of course...if you ARE putting 2 extra sticks on your cp.....consider adding a few extra buttons too and just making it a 4 player cp...again, if you haven't yet purchased your encoder and whatnot...
good luck!