I'm actually asking on behalf of my partner – they're already accepted at some US schools, Toronto, and it's looking like UK, although haven't heard on funding. So acceptance rate isn't a factor, but yes, shorter time, prestige, history, and potentially a better position to make international connections. I agree that well funded Phd programs are good places and nurturing, so trying to weigh that against just going forward with research and getting out into the world. (also we wouldn't do UK w/o funding).
We would like to live internationally (I work remotely), and my partner is very interested in being part of interfaith dialogues and communities, so we are trying to figure that out. Lots of open-endedness, but would also really love to have reasonable options in the States for later in career or fallback.