I used a basic Singer for 30 years. It is a good sturdy machine. Four years ago, my Mom generously bought me a Viking Ruby which I love. We travel to our condo in Myrtle Beach often, and I was hauling my Ruby with me. I decided to buy a Singer to leave there. I can't remember what machine it was (maybe the Quantum). It sold for around $400 at Joann's and I got it on sale for under $300. I have not used it much, but compared to my old machine and my "new" Ruby, the quality does not compare. There is so much plastic on it, I am afraid I'm going to snap something off.
I had looked at the Viking machines for almost 2 years trying to justify the expense. They have no interest financing offers frequently, and if you can go that route, the better machines are well worth it. I know Viking has a great support system, offers user classes, and also classes every month to learn to do projects with your machine. I am sure most of the other high end companies do the same. It is a huge different in price, but the quality of the machine is incomparable.