I work for IBM in Z Systems Management, Monitoring and Optimization. I first started working on Z systems (370 in those days) as a batch assembler programmer. I've also worked on non-Z systems doing early networking to incorporate networked HP printers on ArcNet (who remembers that) so that people on the mainframe could print to local HP Laser Jet printers.

I think the sum of all the IT components is what makes a successful IT shop, not a religious affinity to one technology.