Works great
I bought this for Stepmania and ePSXe and it works great with my dance pad and dualshock after some configuration. However, EMS will not be making a driver for Vista x64 so I had to install it on an XP computer. So, before you buy this, make sure to do some research regarding the drivers and your OS!

Wonderful
Works perfectly with my Red Octane dance pad and Stepmania. Great buy!

Go GO GADGET! USB!!
This precious little object enables you to enjoy your gaming experience like never before. You can attach various PS2-related gadgets like guns, controllers, and dance-pads. Furthermore, you can maximize your game experience when playing 3D related titles like Halo to 2D titles like M.U.G.E.N, Metal Slug, and Stepmania(a free Dance Dance Revolution simulator that can be downloaded at stepmania.com)

I strongly recommend this product to anyone who has PS2 controllers/dancepads, and does not wish to waste valuable cash on products like USB controllers. Don't just stand there, get your VISA out and buy while supplies last.

Review with IIDX Controller
I bought this to use with my IIDX controller.

There are some lag issues but they can be fixed (there are many guides on the internet for this.) however it's still quite a hassle.

It's a good product (from what i hear it works very good with DDR simulations), but for IIDX it's fairly standard.

It's good, but....
For most games on my PC, it works flawlessly, but for Stepmania, it screws up a little bit. In Stepmania, It won't let you press down if right or left is pressed (making most heavy songs impossible). Not only that, but it has a verty slight lag that tends to turn my perfects into goods, and my greats into misses. Maybe it has something to do with the pad I'm using, though. I'm using the standard Konami DDR dance pad for Playstation.