I have a GMQ Pro made by the Grace Co. it has 4 poles and I really like it I have a 15" Bailey on it and could go to a 17"-18"
the only things I don't like are: my machine weighs about 60-70 lbs and the plastic tracks keep splitting and have to be replaced (others use Grace frames and the same machine with no problems at all)
the take up pole has to be raised as the quilted quilt gets rolled (I would like one that the takeup pole stays uo high and there is another bar to hold the sandwhich close to the machine bed.