301s were manufactured in New Jersey, 301As were manufactured in Anderson, South Carolina. They are the same machine. As far as a short or long bed, I'd take what's available. I prefer sewing with my machine in a cabinet (which I'm looking for), so a shortbed is better for me. The longbed doesn't fit in a 301 cabinet.
The 301 is not a heavy duty machine as in industrial, but it is capable of sewing almost anything you'd need in a household situation, much more so than a Featherweight. Mine loves to FMQ. She is an excellent piecer, too. She's also light enough to take in public, which my other machines are not.