Don't rule out vintage or used machines, but be sure to take them on a good test drive. Dealers have trade-ins, Craig's list is full of "gently used" machines around here. Sometimes people are downsizing and you can get a heck of a deal on a cabinet system including the machine.
I had a good modern sewing machine back before they went computerized, a major part broke and I could not get it replaced/fixed -- of course, it was not included in the warranty either. For the last 20-30 years I used the same vintage machine that was older than I am the originally belonged to a friend's grandmother. Just this past fall a friend gave me a modern Bernina that she didn't like, I have to say I love the advantages and options but they aren't strictly necessary. For me though, the big thing was the throat size of my old machine was just too small for quilting and other than the simplest things and small projects, I was going to have to find other ways to quilt stuff down.
I don't know the Quantum so I'm not sure of the features you are used to, I can see how it would be sort of hard to go from a modern machine to a vintage one, but the very simplicity has a lot of appeal. You can do your own maintenance for example. Really all a quilting machine needs is a good steady smooth straight stitch, everything else is gravy. Nothing wrong with liking gravy and going full smothered and covered though! And, if you do anything fancy you need a machine that can do fancy stuff. Me, mostly I just straight stitch but I'm trying to learn the new machine.