The United States of America: What is the best thing about United States when compared to the rest of world?

1. Amazing natural things to see: Between Yellowstone, Denali, Grand Canyon, Mammoth Cave, Everglades and White Dunes, US has some of the most spectacular geographical diversity to see.
2. Opportunities: It is not without reason we cross multiple oceans and battle through an archaic immigration system. Some of us could have been in other nations, but still chose to move here. This is because the kind of opportunities here is unparalleled. I have family living in the UK, Canada, Australia and earlier in Saudi Arabia and all of them find US better when it comes to opportunities.
3. Consistency and uniformity: In the past 12 months, I have lived in 3 different regions - North east (Boston), Southeast (Nashville) and West (San Franciso). It didn't take any time to adjust between these cities. There is a remarkable level of standardization. 
4. Friendly people: Before we left for Nashville, some natives of North east warned us that some people might be racists in the south. Actually, our experience was opposite. Living in Nashville and visiting Kentucky and Arkansas, we found the people quite warm and friendly. In all regions, we found some very good friends. Of course there are a few racists, but so does every country.
5. People are optimistic: More than most countries, Americans distinguish themselves by being more optimistic. Although this is sometimes to their peril (excess debt, excess consumption) overall optimism is good.
6. Driving: I like driving and last year I drove 50000 miles with 6 trips between the oceans. During my various road trips (100+ in 10 years) I have met a wide variety of people. I have met a few Germans who flew every year to have road trips (despite having autobahn). For its size and continental extent, American roads are remarkably good and the low gas prices & point 1 means we were always on the road.