I just responded to bob_mcbob's post, which is somewhat like your inquiry. CIA Masters cookware is very nice, but it's made in China. I have one small fry pan of theirs. I have no All Clad Coppercore, but it is copper clad, not steel-lined copper. For the price, I would sooner get Mauviel or Bourgeat Copper, both of which I do use and love. They are heavy, but have more comfortable handles than any of the A-C lines. Also, A-C lids and some of the pans (roasters, stockpots, for ex.) are also made in China.

I have tested the CIA saute pan by sauteing a sliced onion/pepper/garlic mixture in olive oil for pasta. It has nicely rounded shape to aid in turning/stirring, but still politely sits flat on the burner without wobbling. The interior sandwiched layer of aluminum continues from the bottom all the way up the sides for even heat distribution. The handle has a nice curve to help carry the weight of the pan and its contents. It can be used on any type of stove, even induction. It is a well thought out design and pleasant to hold.

The reason for lining them is reaction t acidic foods. Copper like cast iron is highly reactive, and if you cook acidic foods or liquids in them will leave a nasty taste to your food and cause extreme color changes to the food and pan. I am no expert but my understanding a copper linned pan or ketle is ideal for candy making assuming it is not acidic. Jams could be problematic with the acidic issues.

I have both, got a couple pieces of each (copper All-Clad and copper Mauviel with SS interior). I like them both but have to say Mauviel is so gorgeous and a pleasure to use, the workmanship on it is artistry, it looks prettier hanging on my potrack! I believe Mauviel is superior for cooking as well (just as a secondary comment, lol.) When I went to add to my collection I only got Mauviel. One thing I also tried and will never get again, and that's Mauviel (also Ruffoni) with tin interior. It didn't work for me at all... gets all beat up looking right away, difficult to clean, and the tin started to wear off very quickly. As you know, you shouldn't use it once that happens because you'll be cooking on copper, which is poisonous. Best thing I found for cleaning the copper: Bar Keeper's Friend in powdered form, works like magic. Just be sure you don't have a finicky fancy nickel plated collar in your sink drain. I had one and it ate the nickel off/made it turn black in places.