Re: Martha Stewart...
She's 66? Wow - she really DOES look young. I just noticed the photo of the gal using it - and she's doing it all wrong!
First of all she's facing the wrong way, holding on wrong, and instead of keeping her body erect she's slouching by leaning against the wall. Amazing they're selling these things without having a clue.
To use it, you kneel in front of it putting your head in the middle with the padded areas along the back and sides. You grab the front legs at the bottom and pull yourself up into a full headstand position. Using it that way, it's great for your abs, arms, back and will improve your posture - giving you benefits very similar to an actual headstand without the risks. Far better for you than an inversion table.
Funny story about how we lost ours. When we were moving from Seattle, one of the moving guys looked at it and made a comment along the lines that it must be a really kinky marital aid. It disappeared during the move somehow, but I got at least a good 10 years of use out of it (though never as a marital aid).