I love my Tramontina tri-ply. I have some All Clad as well and the two are virtually identical in form and function. I've never used Kirkland so I can't comment on it but the fact that Tramontina is available in open stock would be the deciding factor for me. I chose only the pieces I needed and had them sent to my local Walmarts (free shipping). In this way the Tramontina was cheaper for me than the Kirkland set would have been.

I only have experience with Kirkland Stainless but it has served me well for a couple of years so far. Cooks well, easy to clean, doesn't burn or scorch on the bottom which means the heat distribution is even (if you keep the temperature at a proper level). It is the only thing I will use when making pudding, as my other pots have a tendency to stick. You can also brown meats very nicely. The 5-ply bottoms are magnetic, so I assume they will work on induction cooktops. I don't have one, so I can't try it out.

Of course, Kirkland is not open stock but if I needed other pieces, I would just add from a set that is.

I also do not patronize Wal-Mart or Sam's Club as I understand they ask good brand name manufacturers to produce lower quality items so that they (Wal-Mart) can sell them cheaper than the competition. So I feel you never know what you're really getting if you shop at a Wal-Mart or related store.