It depended on the company. MS interviewers came in khaki slacks and buttoned down shirts. Google came in jeans with lots of ink and piercings on display.
Part of my friend's responsibility was to give feedback to the interviewers. Her students were passing over MS to go to Google, despite MS offering significantly more for a salary. Their interviewers asked her for feedback to figure out why. She had to politely say that Google was seen as cooler. (The cooler impression wasn't just the image gained from the interviewers, it was the problems Google was trying to solve. But, the interviewers added to the company's image of "coolness".)
She held this position probably a decade ago and left after a few years. Things may be different now.