I was reading about the BSR recently and I found a lot of mixed reviews on it. Apparently it has trouble on lighter colored fabrics, and someone was saying that her chalk lines often throw it off too. After reading all of that I decided I'd be better served just doing a lot more practice, so I would be skilled enough to FMQ on any machine. Can't say I'm there yet, but I AM improving! I never test drove one myself, though.
I like having my embroidery machine as a completely separate machine. That way I can still sew as it's working.