I have a Bernina 440 with a BSR. I use it quite a bit and find that every so often I have trouble with skipped stitches so I take it back to the dealer and they 'upgrade' (or something) the BSR and it works great again.
On the other hand I just tried using the BSR to quilt a baby quilt and the top was mostly white on white and it wouldn't work on that at all, but was fine when I tried it on other fabric.