Ask before you buy ... and then there's no surprises!
As a point of interest ... my for machines purchased from my dealer (Janome+Bernina) you can make an appointment to bring your machine in for servicing with a 24 hr turnaround, providing there are not surprises. They keep a good inventory, so in most cases, it is just the 24 or less. For those who live out of town, they will even do it same day, while you are in town for errands, and so you don't have to make a second trip. For those who did not purchase there, your machine goes in teh queue when you deliver it ... and the appointments are kept, with the others filling in gaps between.
A friend of mine learned the lesson the hard way. She bought a deluxe machine at this dealer and was very happy. Then price shopped when buying her serger. Guess what? not long after she had problems with her serger, and the other dealer didn't follow thru. She totally regrets that "deal" ... and recognizes it was not a good deal!