2 Things:
This is the real 6 button controller. I love these to death over the ones with the Turbo switch. My play is way better with `em.
The retrolink Saturn controllers listed above are the cheap imitations. They suck and fall apart fast. If you can find a Sega branded Saturn USB controller, go for it. But they were discontinued in 2004-5 and are real pricey now. Still its my absolute favorite pad for any game that I need trigger buttons for. If it doesn't say Sega, or if it says Retrolink, don't buy it and thank me for saving you $20