Interesting read, in case you’re impatient here is his conclusion:
Bing has some things going for it, and it genuinely tries to advance the conversation of what search can do, particularly in its app. Good! Google needs whatever competition the rest of the world can muster. But in terms of day-to-day usability, at least in my experience, it too often added confusion rather than strip it away. It kept me cloistered within Bing, when all I wanted—what I explicitly told it, with every query—was to go somewhere else. In search, the journey is not the reward; it’s just a journey.