Interesting, especially since I've just started working for Microsoft, in Bing Ads, and a big factor in deciding to come was the interview process. The phone interview involved writing code in a shared environment, the in-person interviews were all nice (hard questions, non-threatening ways to ask), and I (and the other 4 guys who interviewed in my time slot) were told yes/no right after the interview ended.

I assume experiences at large companies vary widely depending on the group, but I was definitely impressed with Bing's interviewing process.