My mom gave me a battery operated ripper made by Wahl. It looks like a miniature neck clipper. It works great on long seams, but the drawback is that you have to get the hang of holding one piece of cloth up and steadying the other one with the same hand that is holding the ripper. Also, it only works when you can get in between the layers of cloth, so it is not for removing quilting stitches.
Dayle