April1930s.com sells a great free motion foot for the 301. My instructor at my LQS was very impressed with it when AnnieRose and I took a FMQ class. AnnieRose did fine as long as she had a Singer needle in. AnnieRose is my newly acquired 301A. I also purchased a 1/4 inch foot and I've never had straighter seams. Now I have a stitch in the ditch foot, which will debut tomorrow. This little machine has done everything I've asked of her. I have no experience with a 15, but I'd go for both.