I prefer the hard dance pads for two reasons -- it's hard to wear shoes on the soft ones (and we put a piece of plywood down under ours) because your shoes kind of "pick up" the plastic, and going shoeless ends up with the balls of your feet developing bone spurs like my friend did. (she was using it as her primary form of exercise)

That said, she lost a TON of weight, and had the nicest butt ever. Shell out the extra for the better, hard dance pad, or retrofit yours with a piece of plexi on the top, and a piece of plywood on the bottom. Your feet will thank you.