We bought one from a QB forum member last year. Cleaned it up, Tri-Flow'd it, and replaced the spool peg then tested it. My wife declared it hers. She says it sews so quiet and easy she's keeping it.
Our case is kind of beat looking too but it's intact other than needing one new latch assembly for the top.
It also needs a new light, there was a 20 watt bulb in it that burned the light housing.
For scuff marks on the case and other plastic parts that wont wash off, I've found Brasso works well. It will clean and polish clear plastic lenses so it won't hurt the cases at all.
Joe