I spent a lot of time combing the net for comments about different brands of machine quilting frames, and found that Hinterberg frames seem to have the best reputation. Plus they are easy to set up and take down. I would wait for a Hinterberg frame to come up for sale. See
http://www.hinterberg.com to see the 3 types of machine frames they have. I just think the Hinterberg is a safer bet than a Grace frame. Some people really like their Grace frames, but I have also seen some complaints about them.