The lap hoop I use is no longer made. I love it because it swivels on a wooden ball and is very easy to adjust for tilt and angle. Also, there is no impediment to the underneath hand.
Prior to purchasing this lap hoop I had tried a more standard type that seems very similar to the Barnett in that it had 3 uprights between the lap part and the hoop part. I found these uprights to frequently be in conflict with my underneath hand. Also the hoop part was not adjustable for tilt and angle (other than changing the tilt and angle in my lap). As far as I can tell from the Barnett site, all of their hoops have those uprights. For that reason alone, I would not purchase one.
The closest lap hoop to the one I love seems to be the Grace, although their lap hoop is square:
http://www.graceframe.com/site/hoops
I see that Hinterberg also has one, but I do wonder about balance with that one:
http://www.amazon.com/Hinterberg-Des...pr_product_top