Lots of MS employees have iPhones, or use Google in the course of work. Responses vary. Fellow enthusiasts may give you the high-five. Your peers, and even younger managers might give you a light-hearted ribbing. Old-timers might give you a ribbing that's jokey on the surface, but actually a bit disapproving. Higher-up executives may actually indicate to you that it's a career-limiting move.
When I worked at Sun Microsystems, my manager & most of my colleagues used Windows. The inside joke was that Java performs much better on Windows than Solaris, but we weren't supposed to say that to our customers.
