I don't have a Grace SR2 but I do have a frame built by Grace Company - the Bernina Frame. I have never owned any other frames so I can only speak from my experience with this one. The machine glides over the bars smoothly. Fastening the leader cloths to the bars is done by velcro and it was difficult to get the velcro strips straight so I adjust when I attach the quilt to the leaders. Also, I'd like a smaller side clip (to put tension on the sides of the quilt). My clips are rather large and when I do a king size quilt, they get in the way. I have added the Red Snapper fastening system and it's pretty good to attach quilt quickly.
If I was rich and had to do it over again, I'd get a system that is all integrated - frame, machine etc. that go with one another.