I vote for the UK top10 univesrity. As you said in your post, the US school is ranked in 70-80. Therefore, I guess it is a public school. For those kind of public schools, the quality of their undergraduate education is awful, since they need to enroll a lot of local students to fulfill their duty as state funded public schools. Because the faculty to student ratio is very low due to the large amount of students in these public schools, some of the classes are taught by gradute teaching assistants like me.
In the UK top 10 school, you have chance to be taught by world class scholars and most of your classmates are high profile students selected from a large application pool. You can not only learn from your teachers but also learn from your classmates, not to mention the chance to get access to a powerful alumni network.
If money is not your problem, just go for the top10 UK school.