I didn't realize this was in Shop Talk. Perhaps if I were a restaurateur and wanted peak durability, I would try to find a way to make steel work. Plenty of professional bakers use sheet pans, though.
I bought aluminum sheet pans, as well as steel pans, while I was trying to duplicate New York Sicilian, with which I am very familiar. The steel pans didn't cut it. They just didn't brown well or create crunchy crusts. My aluminum pans make the best pies I've ever eaten anywhere, and they don't stick. The crusts are crunchy, and I can get them as brown as I want.
No professional shop I've tried has ever come close to my pies. I have no reason to ever buy a Sicilian pizza again, because I know I do it better.
The pans I got may well be from Allied. They are the same pans I saw in New York pizzerias. That's where I got the idea I needed them.
They are mild steel, 12" square, with thick wire in the rims. I bought them from a pizza supply company. They look exactly like the Allied BB1212. They are sitting in my cupboard behind some cake pans I never use. They have been unused for about 13 years because they didn't compare to sheet pans. I'll post a photo.
I tried to throw my steel pans out, but I felt bad about it after spending money on them, so they sit and collect dust. I considered giving them away, but I don't know what they're good for. When I teach people how to make Sicilian, I tell them to buy what I bought.
I see them selling for $28 each, which is crazy. A quarter sheet, made from aluminum, which is costlier than steel, is around 5 bucks. Granted, it's a little smaller, but it also has more edge per unit of area, and nobody wants a slice with no edges! Everyone hates those inner slices. Also, you don't have to worry about aluminum rusting. I just clean the oil off and put mine away. My steel pans got wet at some point, so if I ever learn of a reason to use them, I'll have to sand them and re-season.
I'm sure steel pans have their virtues, though. If you say they're great, I'm sure they are, for the right people.