For true "premium" quality I'd look for stainless steel, and at stainless steel prices, I'd expect everything to be really spot on.
I have the same cage Michael does except mine has the playtop. I'm actually a bit happier with it than he seems to be, my main complaint being the food door latches, which are very easy to not close properly.
Michael wrote:For instance, on Truman's cage the rails that hold the poop pan are very small and hard to line up with when sliding the pan in. I would consider this a design flaw and unacceptable for the price tag of that cage.
This is true, it is a pain, but I've discovered the sliver lining -- you can pull the tray most of the way out without it falling out, so I rarely actually remove it all the way.
Another stupid flaw like this is the notches on the food bowls. They have two bulges that stick out that line up with notches in the food bowl rings so that you can drop the bowl in, twist, and then it cannot be lifted. Well about 3 out of 8 bowls I bought have these bulges misplaced so you cannot drop the bowl straight into the ring.
While I find I need to fiddle with them to get them lined up, none of the 5 bowls I have fail to line up. You might want to lodge a complaint about this.
Another thing is that the cage panels do not line up to each other exactly. Some are as much as 1/16"-1/8" off.
I don't see this at all on my cage. Are you sure all the panels are turned the right way? Mine's tight as a tick, with all the grooved sides of the long rails facing in. You may have gotten a lemon, or maybe even mis-oriented a panel.
I'm not sure King's Cages are the best thing since sliced bread, but I actually have a couple of complaints about my Avian Adventures cage, too. The latches get very stiff, and half the cups I have for it don't fit the feeder rings at ALL! As in the sitter forced them in and it actually cause the metal to fracture, resulting in thrown away stainless steel cups.
At any rate, once you get past materials and basic workmanship, the rest is size and features.