Poosterman ... The grace frame is so smooth! I "test drove" a longarm ($15,000) at a recent quilt event. The longarm is smooth BUT the sewing machine is pretty heavy and has a lot of momentum... could take lots of getting use to and practice. The Grace frame is a huge step up from hand held FMQ.. and cost is well under $1000.
I got my frame used, BTW, and I feel that used would be the way to go on these. Check craigslist. If you have a choice, the metal Grace frames are probably better for the long term.