I have a Viking Platinum - couple models older than the Sapphire. My friend has the Sapphire but not sure if it's the 930Q. We each paid about $1200 new for our machines - about 10 years apart. Neither of us do FMQ so not sure how helpful this info will be for you.
I love my machine. Have never had an issue with it at all. It will sew anything I throw at it (except the binding on a boat cover!). I have done machine quilting with it - just not free motion. Since it has an auto tension, I did not have to make a single adjustment; no need for a walking foot either.
I want to think my friend did a rag quilt on hers with no issues/walking foot either. She bought her Sapphire about 3-4 years ago for $1200. So I would think $700 is pretty reasonable but couldn't hurt to try to negotiate??? I certainly would. Since it is at a dealer, are they willing to give any kind of warranty?
Hope this info helps. Good luck.