Heh, Reading @ Wiki on the super advantage joystick, it says the slow button should "slow" down your game, although when mine is on, it seems to rapidly press start and select alternating...

it does not slow my game down...

o_O is it suppose to do that? or what really is this slow button?

Yeah this is what Slow Mo on controllers does.  It basically just rapidly pauses and unpauses the game.  Works well for something like Super Mario Bros, or anything where Start doesn't bring up a sub screen

Thats pretty pointless >_>

All slow-mo pads do that. It's not gonna work on games like zelda where it brings up a menu on pause. It works best on shooter games and platformers like r-type or mario brothers.

Heh, Thanks .

A note about the Super Advantage by the way:

It's made by ASCII of course who made some of the best Super NES controllers out there - most of which actuaally carried the Nintendo Seal. 
What I just found was that ASCII actually made the original Advantage too, but it was released as a "first party" controller if you will.