I still have a quilt ring (had no idea that's what it's called) that came with my Viking Rose bought about 2001. I've only tried using it once or twice, as I've discovered that Machinger gloves do as well or better for me. This thread has inspired me to try it again.
It's good to hear others have success with the rings on larger quilts, as so many demos only show using them on small practice pieces. That's how I got suckered into using quilting ruler templates; it looked so easy when the demonstrator did it on 18"x18" pieces! Not quite the same on a full quilt, IMO!