You can build a nice pad out of a softpad, a slab of playwood and plastic hardwood floor covering. Cut the plywood to just a little bit bigger than the pad dimensions (2-3 inches more on each side), put the pad down, tape it down, then lay the plastic down. It'll make it feel a lot more like an arcade pad and extend the life of the pad quite a bit. It'll add about 25-30 bucks and about an hour or so of work, but it's worth it.
This is of course assuming you've already tried the game and liked it. If not, go to an arcade and try it out. If you need to find an arcade with DDR, go to ddrfreak.com