I've had an 850 Sapphire Quilt for almost 2 years now. It took some getting used to.
When my bobbins start to act up, I rewind them onto an empty bobbin and that frequently clears up any snagging problems.
Also, changing to NEW (good quality) thread and changing needles frequently seems to keep me from having issues.
Using leaders/enders when piecing also prevents snags on the fabric. Change needles frequently, too.
Like I said, I was wrestling with it a lot, and I did take it in once during the warranty period, but after a few months, we both "got to know each other" and it's been a match made in heaven ever since.