the acufeed feature is not at all intended for free-motion. it has nothing to do with free-motion. it's for sewing and is a superior alternative to a standard walking foot.

i just about never use anything but the acufeed for sewing. i will never buy another machine that doesn't include acufeed. i have much better control over the fabrics as they go under the feet than i can ever achieve with regular feet. for quilting in straight or curved lines it performs like a champ, too. it also makes binding a breeze.