I am sewing on a Singer 503 - the tan color Rocketeer. I purchased my first 503 in 1963. This was Singer's top-of-the-line home machine at that time. I don't remember how much it cost, but I paid for it at the rate of $15 a month for a long time. I have sewed everything on that machine: dresses, evening gowns, parkas. bathing suits, costumes, even made my husband a pair of trousers and repaired pull straps on cowboy boots. Never had to have it worked on, I kept it clean and applied oil and lubricant when needed. A few years back my daughter gave me a Viking machine which she paid about a thousand dollars for. It is sews fine, but it cannot sew heavy seams and it sews way too slow.
In 2015, the old Singer had some parts that were wearing out, so I watched the estate sales and found one just like my old one. I had to pay $125 for it. I am now sewing on this one, my "new" 50 year old machine.
Since I got the second 503, I have made 12 quilt tops. PJ's and dresses for great-grands, a teddy bear, market samples and curtains. I altered blue jeans for my granddaughter and repaired a pull strap on a pair of boots.
Yes, there are Singers that don't sew well, but ask anyone who has ever had a Singer 500, 501 and 503 and I don't think you'll get any complaints.