Comps are better then ultimates... Ultimates are great if you don't have the other sitting next to you to compare though.. But if your buying them.. go with Comps
Supers don't have corners. You can spin them in circles smoothly. Better for TimePilots and Gyruss, but not as good for fighting games.
Mspacman Ann 4way is a GREAT 4way joystick.
Most don't like their button top joysticks. One is for crane games and SUCK... The other has a pretty stupid top but I hear its ok -> good...
Consider others also... I like the idea for space for the top change 4/8way joysticks TStick from Andy (and where you might want to get the trackball). I haven't tried them but I hear they are good... Smaller throw... But the reviews talk about them.