I bought a Babylock Sashiko machine last year and love it. I intend to do alot of quilting with it for smaller quilts. Initially I had thread breakage, and quickly realized I was causing the problem by laying my hands heavily on the quilt while it stitched, and this was causing some tension, which would make the thread break. Once I gently guided the quilt instead of holding it the way I do when piecing, I had no more thread breaks. None!
I do not consider it "an expensive one trick pony" any more than I do my television, washing machine, refrigerator, longarm quilter, computer, or embroidery machine, all of which only do one thing and do it well.