I don't have the 820, but I do have the Aurora 440 with the BSR. If you are already comfortable with FMQ, the BSR is a waste. I have more problems with that and end up FMQ using a regular spring darning foot.
However, the larger opening is WONDERFUL for quilting. the stitch selection is also wonderful. I recently bought a Brother machine - A Laura Ashley Limited edition. The 440 is a basic Cadillac, the Brother is a KIA with all the bells and whistles. I love the thread cutter, the automatic needle threader, the pivot option. Those are features shared by the 820. Those are worth investing in.