The Presto pressure cooker with the rocker-weight pressure regulator has been manufactured for at least 50 years, and in all that time, the design has hardly changed at all. The overpressure relief plug and the lid-lock plunger have been moved to different locations in the lid and handle, and the design of the plunger has changed slightly, but other than that, my new 8 quart cooker is identical to my parent's 6 quart model that was made sometime in the early 1970's. The product hasn't changed because it doesn't need to; it does exactly what it is designed to do, and does it simply and efficiently. I only bought this new one because my old one was so stained, scratched, and ugly that I was embarassed to have guests see it in my kitchen. The old one still worked perfectly. I use mine almost exclusively for pot roasts, but there are hundreds of other recipes for pressure cookers. This model is set to operate at 15 pounds per square inch steam pressure, which yields an internal temperature of about 250F. It cooks 5 pound pot roasts in about 1 hour, and will reduce even the cheapest, toughest chuck roast to fall-apart tenderness. If your cooker starts leaking after a few years, replace the seal ring, the overpressure plug, and the gasket on the lid-lock plunger. These three items are all available as a kit from Presto for about $10 and will extend the life of your cooker indefinitely.  CAUTION: If your cooker is ever accidentally overheated (by allowing it to run out of water), or dropped on a hard surface and dented or damaged, it must be replaced. The aluminum metal of the pot or the lid could fail catastrophically (explode) on a subsequent use if weakened by overheating or physical damage.