Ritzy's right--slowing down does help when you are learning how to use the BSR. Part of the reason you may find the movement "jerky" in the beginning is that your hands may also be moving the fabric too quickly. You need to find a steady rhythm for your hands as you do your free motion quilting FMQ). Also important is to make sure your needle is set to the "needle down" position so that when you stop to reposition your hands, you are not accidentally moving the fabric. Try not to be tempted to move your hands while you are doing the FMQ--that causes "jerky-ness" too. Finally, not sure whether you are an experienced quilter, so I make the suggestion on the assumption that you are learning: move your fabric east and west, north and south with your hands but don't try to turn the fabric while FMQing--that causes "jerky" movements too and can break your needle because the machine is designed for the fabric to move from the front of the machine toward the back when you sew. Finally, don't forget to BREATHE while you are doing it! If it is not fun right away, as you get better you will have a blast: yes, practice, practice and more practice (which I am still doing a lot of!)
Personally, I don't use the BSR even though I have it, it came with my Bernina 830. I have used it both in the BSR 1 and BSR2 modes and concluded that I much prefer to work without it. Some people suggest that the BSR is the answer to those who have a hard time getting even stitches, but the truth is that no matter whether you work with or without BSR there is a learning curve either way, so be patient.The BSR, once you've established a comfortable rhythm, will start to produce great results often faster than if you were working without BSR. Some people use the BSR as "training wheels" while they are learning to do FMQ and then move on to working without a BSR. It really is a personal choice. Hope this helps!