I have a smaller one that I can use on the couch. It's about 16"-18" square. It's okay, and I do like being able to adjust the tension in my piece, but it's difficult to quilt with as I would prefer to "prop" it on something so both hands are more free to work with.
These floor models can be found at my local Joann's, for around $169, I think. I though that was just a whole lot to pay for some PVC pipes, but that's just me.....
If you really like it, then perhaps you need to spread the word --- maybe Santa can bring you one especially from the North Pole for Christmas???