The more I read, the more I like. Substance.
Experience. He consistently seeks out challenges and then goes "all in". He's worked in Democratic politics at the state and national level. He interned for Kennedy. He was offered a position in the Obama Senate campaign but turned it down because he was confident that Obama would get the Senate seat without him (he did), but saw Kerry-Edwards as being more in need (they were). Harvard is "meh", but earning a "First" in the Oxford PPE program - philosophy, politics, and economics program - is a huge, huge deal. The method they use is one-on-one or two-on-one mentoring - every week you teach yourself as much as you can about a topic and then meet with the mentor(s) to discuss what you've learned - essentially an oral exam each week. That must be an amazing experience that sets you up for life-long learning in any and all fields of interest.
He joined the military after Harvard, after Oxford, after earning $$$ working in the top consulting firm in the nation because he thought he should - it was just the right thing to do. In generations past, fortunate sons (Kennedy, Bush, etc.) were more likely to serve than other socioeconomic groups. When he was knocking doors in Iowa he encountered family after family who had a child on their way Afghanistan and the number of graduates from his Harvard class who served could be counted on one hand. He thought he should serve - so he did.
Intellectual powerhouse. Experience in business, government, and the military. Clarity of vision regarding climate crisis and economic realities in the U.S. Strong, long-term support from minority leaders in his city. Democratic Party loyalist. Tech savvy. Evidence-based decision-making that utilizes expertise from university instructors and students. More...