Not Perfect
Given that it is more expensive than your regular usb converter (there are MUCH cheaper options at parity performance) imo it's not worth the buy unless you really want the force feedback (FF). I notice a fraction of a second delay when playing fighting games on my PC using a pad, probably due to the increased wiring brought about by the FF function. The difference is not noticeable in other genres, but with fighting games it could be the difference in a highly competitive match. So if you plan to use this for an arcade stick and don't need the FF function, not worth it.

was awesome
it work perfectly i hooked up 2 pads and they work if its not workin out for u first hook them up to the converter then plug it in

Works perfectly!
I tryed it with a ps1 controller on 1 port and a 'hori fighting stick 2' on another port and it works perfectly! I played GGXX #R and ssb64 on pj64 with no problem. Didn't try all ports yet. Need to buy more controllers...
I have Windows XP pro on Desktop, didn't have to install any drivers.

Works Great
I just got my SJ5P in the mail today and it works great. I am running mutiple controllers just fine on a laptop with Windows XP Home. I just installed the newest driver's from Mayflash's website and the controllers work flawlessly when playing games on any of my emulators. The controller response time is perfect too; great for fighting games. Best purchase I've made in a while.

Definitely not awesome
This product sounds great, but it's not. As reported in many other reviews, it only works consistently with a single controller. I've hit this with original playstation (PS) controllers, original PS dual-shocks, and three different brands of dance mats.

With multiple controllers there will be one that works perfectly, and the rest will flicker between their real input and that of another controller. Unless you're trying to amuse a three year-old, that makes the multi-controller functionality completely useless.