I bought the Leadergrip system - similar product. I am very pleased with them, quick and easy to load/unload - I found that pressing the bar to attach the quilt requires a little practise to find the right balance of position and pressure to get it to snap easily.
Also, mine were so tight that I had difficulty getting all three layers on when required, so I bought a length of dowelling that was a little bigger diameter than the round guide pieces and left the grip part snapped onto it for a few days - repeated with enough lengths for width of frame. I now keep these pieces for three layer attachment. The dowelling was just big enough to stretch the grip part a little and now it snaps on well, without being too loose.