I have a Featherweight (among other machines) and might not recommend it for someone's first and only machine. They are small and portable, which makes them great for taking to quilt classes for piecing, but they are not strong or fast. You also need some sewing machine experience to know if the machine needs cleaning, oiling or re-wiring, due to it's age.
I agree the best thing to do is go and look and talk to a local dealer where your wife could take a few classes with her new machine. It's good for a beginner to have that kind of help.