I seen it in an infommercial and it is supposed to whip even black coffee into a frothy confection, mmmmmmmm. Has anyone purchased this and does it really work?

but I do have another version of it. It does work well for blending and frothing. I don't know if it'd go so far as to make black coffee into a "frothy confection" - -

I think mine is a Braun...there are alot of similiar ones out there and I think they're probably about the same price. $50 - $75 I think.

I have seen the info on the Thunderstick, I don't have that one, but have a Bamix for which I paid quite a bit. I love it, I recently used it to make applesauce and pea soup, right in the pan. No more putting in the blender for me.
Yes, it does make the coffee frothy, and also whips skim milk, to which I add some instant coffee and Nestle's Quick for a yummy (fat free) mocha milk shake.