There are a lot of choices when buying a pressure cooker: domestic or imported, stainless-steel or aluminum, large or small, hissing jiggle top or no-noise regulator. After preparing the same recipe in three six-quart pressure cookers--a low-priced jiggle top (Presto, $65.98 retail); mid-priced jiggle top (T-Fal, $119) and an expensive built-in-regulator model (Cuisinart, $230)--I found you don't necessarily get what you pay for.
To evaluate the cookers, I cooked with them for a couple of weeks. Then I prepared citrus rice with currants from Lorna Sass' "Great Vegetarian Cooking Under Pressure" in each model. Leeks were sauteed over medium-high heat, rice was stirred in, then liquid and currants were added. The lid was locked in place and the cooker was brought up to high pressure and maintained at top pressure for three minutes. The pressure was then allowed to come down naturally for seven minutes.
I found very little difference in cooking performances. Only one, the Cuisinart, gave me any trouble. Locking the lid in place was tricky, and by the time I finally succeeded, too much steam had already escaped and the rice was scorched. It took three attempts before I cooked a perfect batch of rice. Twice in a different recipe a vacuum formed inside the cooker as it cooled down, and I could not get the lid open. Both times I placed the cooker back on the heat and warmed it for several minutes; then the lid opened. It was very frustrating. If I hadn't borrowed the cooker from the company, I probably would have thrown it out the window.
I also found that the weight variance between the three cookers made little difference. The lighter weight of the aluminum model is actually a welcome benefit, especially when the pot is full, but aluminum can leech into acidic ingredients such as tomato-based sauces.
Recommendations: I find it hard to justify paying $230 for a pressure cooker, no matter how pretty. The less expensive Presto and T-Fal jiggle-top models worked just fine. Besides, the jiggle top's occasional hissing is a comforting reminder that dinner is cooking. All three had two handles, which helps in lifting when the cooker is full.
Since you can only fill a pressure cooker three-quarters full for most dishes, and only half way when preparing beans or grains, you shouldn't buy anything smaller than a six-quart cooker.
Don't be enticed by multiple pressure settings either. Most foods are cooked at high pressure. If you're tempted, just think about those first VCRs where you paid extra to be able to set a timer to record up to 20 programs while you are away. I still don't know how to set it for one, let alone 20.