I love the open metal circle foot, with spring. I have tried the plastic ones, the closed metal circles, and others that came with machines. I was so frustrated trying to fmq (after taking fmq classes from three different teachers). At last class another student noticed my quilting foot and said here borrow mine and try. It felt like a total different experience with the open-circle metal/spring quilting foot (sometimes called darning foot). It also has the arm that hooks over the screw so the foot goes up and down nicely. It still takes lots of practise to fmq, but I am now improving since I got this type of foot.
Good luck and I hope you find a foot that works well for you and your machine.
Kat