Seam rippers have been a pain for me ever since I have been a quilter. I don't break them, they just go dull in a very short time. I have many, many, of them in drawers and boxes.
But I have found the perfect seam ripper. It's made by Ghingher and a little pricy but with your Jo Ann's cupon you can get one at a reasonable price. The retractable blade is very sharp and stays that way for a very long time. You also can buy replaceble blades. It is not made for poking the edges of a corner out. To do that buy the wooden or plastic thinghy's that are made for that purpose. I give them as little gifts because quilters never seem to buy the right tools for themselves. I make them special by tying several pretty ribbons through the holes.