I free motion on a Janome 6600, and I bought this machine particularly for doing fmq. I've done up to king size, and not in sections but working on the whole quilt. I dont mark a design, I prefer to work freehand, and I certainly dont just "make squiggly stitches all across the quilt". I practice before using a new design, I spend alot of time with pencil and paper to improve my drawing abilities.
It takes a bit more patience and effort to do freehand free motion on a domestic machine, but the results are well worth it.