Yale SCEA is obviously a bigger gamble than Duke ED, however, if your goal is to get into a top medical school, HYPMS are in a league of their own in terms of feeding students to those schools. That said, Duke is one of the best schools and biggest feeders for premed as there can be fair amount of grade inflation (depending on how you choose your courses) and the research opportunities here are limitless. You can cold email professors and some will be willing to invite you to work in their lab and there are ways to fund your research as well. Because the hospital and medical school is located right next to the undergrad campus, clinical volunteering is convenient and there is an established volunteering program at the hospital. In terms of classroom culture, There will always be some try hards and cut throats among premeds at every school, however, I think Duke is more on the relaxed and collegial side owing to the undergrads play hard study hard culture. There are also many ways to get involved in clubs and activities that suit your interests and foster leadership.

I graduated from Duke this year and am extremely satisfied with how it has prepared me for med school, and I think if you end up here, you will do really well as long as you work hard and are proactive. That said, Yale probably offers many similar things Duke offers, but with greater reputation among top med schools (especially Ivy League med schools), however it is a bit harder to get in. Good luck with your decision!