Again, I will make the price comparison (must be in my DNA) - I have recently bought one of these for the princely sum of $299 as nothing is cheap over here. It has saved lots of back aches, but I could have it a few inches higher still.I think one with adjustable leg height would be ideal for some of us taller "girls" as we are not all 5'2" any more.
I was inspired to get it as I christened my friend's more expensive one ($799) during the Christmas break and noticed the difference to my back.