I like stainless steel...
Cuissi, King... Simple, classic, and without the blackening that you get with Al cages. And if one gets bent, you can bend it back into shape well enough to work. You can't do that with Al. You can get them online for as low $15.
I did break a Cuissi stainless cage once. I had a full, large size water bottle in the cage and during a lovely early morning ride in Yellowstone. Gorgeous. Highly recommended. I was riding over one of the many stretches where the roads are broken-up and crumbling. One of the bottom tubes on the cage on the seat tube broke. It took me awhile to figure out where the rattling sound was coming from.
I should have tried to get it replaced under warranty, but I tossed the cage before I thought to do that. I had had it for several years.