Applied online late last year, got a call for a phone screen after 4 months. Apparently Microsoft had fired many recruiters and just ramped up on recruiters earlier this year.
Phone interview was standard discussion on programming languages, a question on how to test a phone, and a coding question on binary search trees. Straightforward stuff.
2 weeks later was flown on site. Had 5 interviews including the recruiter/HR. Questions ranged from : find a string query in a string pattern, find the smallest integer repeated an odd number of times, remove characters from a string without using additional space, to testing questions such as test a vending machine and test a traffic system. The questions were not that challenging but the focus was on finding edge cases and bugs.
The interviews were easy/average, especially when compared to SDE positions. Unfortunately it seems that the negative perception of the SDET position is true: I found that the recruiter and the lead were trying a little too hard to sell me on the SDET position by stating how it is considered the same level as the SDE and/or PM level and there is no difference in salary (if this were true then there is no need to state it during an interview). I blew through the questions with ease and they probably thought I wasnt a good fit even though I was interested in the position as the group was an exciting one to work for and I have and interest in both development and testing.