Sorry, I don't have one but thought about getting one too. I just had to say good one, LOL!!
I will say that anything that helps give you better form for crunches would be a good thing I would think! It's cheap, too.
I have one - it actually works REALLY WELL. I have a huge territory, and I take it with me on overnights. It's only $20 or so with the DVD....you should get one. But watch them try to "sneak" extra sales. They did something like an autodraft every other month to send me newsletters and crap I didn't want. They had billed me in advance for one month - I called and yelled at them and they credited me. Good luck!