I actually have a couple, and they are so adorable. I have used mine and they are really fun, but when it came time to actually quilting, well the Featherweights had to take a backseat to my other sewing machine, the much loved Bernina.
There is no straighter stitch than on a Featherweight, as they are not capable of any side to side movement. They are very simple to work on. David McCallum wrote a book, The Featherweight 221 and I, which includes very clear and easy instructions on how to do the tune ups and repairs. He is from this part of the country so took a class from him. It was lots of fun. I would never let anyone else repair or tune up mine now that I know just how easy it is! :)