I've found catalogs online for Square-D, Cutler-Hammer, and GE (not very impressive). I search around the Siemens web site, but I could not find their catalog at all, nor any web pages that would be equivalent to a catalog.
In my line of work, which includes designing data centers, I have specified the needed wiring, including the panels. I've gone with Square-D in the past, but today I would include consideration of Cutler-Hammer (and probably specify a choice in each). I wouldn't touch GE. I have no knowledge of the Siemens product line.
