I purchased a Bernina 630 2 1/2 years ago, and have had nothing but problems with it skipping stitches just like you all are describing. I can use the BSR for thousands of stitches of sewing, and it will work perfectly, then all of a sudden it will begin skipping, and then all of a sudden it will begin working correctly again. I never have skipped stitches when sewing with any other foot, only the BSR. I have had it back to my dealer 5 times and they always say they cannot figure out what's wrong. I have done some resesarch concerning causes of skipped stitches on any machine, and one of the things that will commonly cause skipping is improper stitch formation which can be caused by the presser foot tension being set too light. If the fabric is allowed to "tent" up when the needle comes up out of the fabric it can cause the bobbin thread to not catch properly to form the stitch. My fabric sometimes does tent up. I have also occasionally heard a "ping" sound when the needle comes up out of the fabric when sewing as if the thread tried to catch but didn't. The manual and all training I've had says to put the presser foot dial at 0 when using the BSR. I decided to send Bernina an e-mail and ask them about this setting, and just got an e-mail back saying that the manual is wrong, and that the presser foot tension dial should be left at 47. I'm wondering what those who are having this problem are putting your presser foot tension setting to? The suggestion from the dealer that there is a spring that needs replacing seems to be something to have my dealer try. It is there now waiting to be looked at, so I'll pass this on to them in hopes that it might work.