I bought a refurbished Janome from a gentlemen who does sewing machine repair/maintenance. He offered a 1 year parts/labor on the machine. I haven't had a bit of problems with it.
I bought a new machine (Janome) in a sealed box from a dealer and it has been back several times in the year for issues.
Basically, I'm happy with both machines once the bugs got out of the new machine. I wouldn't hesitate to buy a refurbished machine but then again I buy used cars too.