I work on the Power BI customer advisory team (CAT) at Microsoft and spend my days tuning very large and complex Analysis Services data models. I learn plenty as I go, and primarily use this website to share what I can. All statements across the DAX.TIPS website are 100% independent from my employer (Microsoft).
I have a couple of books available on DAX for Power BI
Feel free to reach out to me on twitter : @PhilSeamark