dance dance revolution pad question ?

Ok, i was looking into buying a USB DDR pad to go with my PC. After reader "customer reviews"  on the net, some person was saying that you couldnt press 2 keys at the same time ?

I was wondering if anyone else is a USB pad and got them to work perfectly with the game ?

also, would you recommend or advice me not to purchase the following ?

http://cgi.ebay.ca/2-Dance-Revolution-USB-Pad-Mats-for-PC-MAC-COMPUTER-PS2_W0QQitemZ180072348418QQihZ008QQcategoryZ21188QQrdZ1QQcmdZViewItem

From what I\'ve, people say that "Ignition" are the best pad out there, but they don\'t seem to make USB or multi plug type for pad.