I just replaced the Happ Ultimate sticks in my cabinet with Happ Supers.  I'm amazed at the difference!  The balance between diagonals and straight directions is so much better; with the Ultimates, it was almost impossible to move in a straight line without veering to the diagonals.  Even though the stick is in 8-way mode, 4-way games such as Pac-Man and Donkey Kong are so much more playable now!
--Chris