What's an SDET?
Here's a post someone just showed me by Scott Louvau in June 2005 that may give you more insight into what the SDET role at Microsoft is all about.
https://blogs.msdn.com/scottlo/archive/2005/06/29/434121.aspx
Scott touches on a few key points about the role:
1. It requires strong development skills
2. SDETs must enjoy testing
3. You get a broad perspective on the products you test
I've been an SDET for over 9 years at Microsoft now (where has the time gone!) and I still think it's the most flexible and interesting position in the industry. If it sounds like something you might be interested in, check out our open positions.