I agree with Shady, Princeton is probably the most similar top US university to Cambridge (or Oxford, for that matter).
At both places there's lots of attention on undergraduates and super high academic standards.
The differences are pretty obvious (3 v 4 years, tutorials v no tutorials, only CompSci vs Liberal Arts). No one can tell you which is better for you, you can just make a choice for yourself based on these differences, and know wherever you end up you'll get an awesome education.