Cookware sets are a poor value because they end up having lots of items that you'll never use and since no single kind of pan material is best for all purposes. It's better to buy specific cookware pieces individually for a specific task. Stainless cookware with a copper base or core is overpriced and no better than aluminum core/base. The most important thing is to get a good heat spreading metal on bottom and up the sides. Here's some examples. It's good to have a couple non-stick commercial grade aluminum skillets specifically for eggs and omelettes. Stainless clad pressure cookers are better for pots because they have very solid construction and heat spreading, and can be used for regular cooking, pressure cooking, and steaming. Getting 4qt, 6qt. and 8qt pressure cookers are far more versatile than regular stainless clad pots. They can do many kinds of recipes 70 percent faster. For frying, a nice deep sided cast iron fryer with lid cooks better than stainless. A couple good stainless clad specialty pieces are useful, like a double boiler, a pasta insert for the pressure cookers, and maybe a saute pan or two. I used to buy sets because I thought it was cheaper per piece, but then I realized that I didn't use half of the set since I always used pieces that I bought that were better for specific tasks.
Visit a restaurant supply store to see what they sell, and what they don't sell. They don't sell sets, and they don't sell expensive copper clad cookware. They sell lots of all-aluminum items, stainless with aluminum heat spreaders, and aluminum non-stick. If they sell copper, it will be specialty items like copper mixing bowls for doing meringues with egg whites. Expensive consumer products like All-Clad won't be found there. Few restaurants will buy them.