I have the Grace Queen frame for my Brother 1500. Yes, the quilting area could be bigger and you do roll the quilt a bit, but if you don't have the money for a true long-arm (like I don't), then this is a nice alternative.
When I get past the middle of the quilt and the area starts to get a little smaller, then I stitch enough and pin enough to "baste" the rest of the quilt, then take it off the frame and turn the quilt around and load it back on the frame bottom up with all the layers together on the take-up roll. That gives me as much room to quilt on the bottom of it as I do on the top.