I have the BSR foot for my 630. I am still learning how to use it. I have only used it a few times and those were always months apart. I am using it this evening and having to relearn the stupid thing. I'm not sure if it is making a huge difference since I have not tried to FMQ without it.
The trouble I am having tonight is not necessarily a problem with the BSR but trying to get even petal shapes on a queen size quilt. I keep hitting my hands on the edge of the machine and then end up with a little "jerk" as I try to adjust the quilt to be able to work on it.
Not sure If I am explaining myself clearly.
I think if I used it more often, I would get better at it!