I think most undergrad degree courses in the US is 4 years and 3 years in the UK unless you want a year in industry and/or get a masters as well.
Most undergrad degrees in the US seem to have a major and a minor when you have to study two unrelated subjects while that is rare in the UK and most degrees just do a single subject.
On the plus side, its probably easier to stay in the US after your degree because the UK govt is trying to get rid of anyone useful after they graduate. If you want a overseas student friendly country to study, Australia is a good place.