Reputation and variety
Among top-tier American institutions, billions of dollars are invested into university research, average graduate salaries are high, and student to staff ratios are low.
In world university league tables, hundreds of universities in the US rank comparably to or higher than UK universities:
University rankings should be taken with a pinch of salt though, and should not be the only metric by which you choose an institution. There are many more important factors to consider.
There are also over 4,500 US universities offering undergraduate degrees. With such a wide range of universities and degrees on offer, you can find an institution that fits your academic and personal needs.