I have owned several different kinds of pads. I've owned a first-party Konami pad, the cheap Mad Catz pads, some other off-brand flat pads, the Ignition 1.0 pads, the Ignition 2.0 pads, and an assembly-required hard pad made of sheet metal. Before the Ignition 2.0 pads came out, the 1.0 pads were the best you could buy. Now I don't think they sell them anymore, and the Ignition 2.0 pads are the same price but with additional foam padding and a better non-slip surface. They are excellent pads and have gripped both carpet and tile better than anything else I've used. The Mad Catz pads are $15 each but they slip all over carpet and tile no matter what you do because the back is the same vinyl coating as the top. They also break after about 30 to 60 days of regular use. The Konami pads are a little better than the Mad Catz pads, and they won't slip as much on tile, but carpet gives them a lot of trouble. They also won't break like the Mad Catz pads, and should last you a lot longer. Due to the weight of the foam inserts and the rubber non-slip surface on the bottom of the Ignition pads, I've never had a problem with slippage. They cost more but they are worth the money. Don't bother buying metal hard pads. If you don't wear shoes, you can cut your foot, and if you do wear shoes, you can dent the pad (and I'm only 120 pounds). Also, the sensors are wonky and tend to give out or stop working. The other bonus of the Ignition pads is that you can feel where the arrows are under your feet, which doesn't happen on any other pad except for the hard one that is prone to breakage.
Before the Ignition pads existed, I used some modified Konami pads. I cut two sheets of plywood to just slightly larger than the size of the pad, put the pad on top, and then wrapped the whole thing in construction-grade plastic sheeting and stapled it in the back (be sure not to staple the pad itself to the board because you will cut wires and then the pad will not work). This solution works fairly well but ends up costing almost as much as the Ignition pads, and you can't feel the arrows, and they are a lot heavier to move, and the plastic cover tears with regular use (even with stocking feet) and you have to replace it about every six months. The pad isn't damaged though.
If you have the money, you can buy an actual DDR stage, like the one that attaches to the arcade machines, and an adaptor to make it work with a PS2. However they were only sold in Japan, there were a limited amount of them, and I believe the original asking price was something around $1500, and it probably hasn't gone down since. These days you could probably buy a complete arcade DDR system for that price, as long as you don't mind settling for an older mix like 5th Mix or Max.
