I bought this atlas for my family's 6000 mile roadtrip across the country. The atlas proved to be very useful--especially the large, detailed maps of downtown metropolitan areas. Having never been to Philadelphia or Washington DC before, I could easily have gotten very lost had it not been for the guidance of these maps. Another useful feature of the atlas is the mileage chart for each state, both the standard city-to-city mileage and a very useful "places of interest mileage" table, which gives the distance from major cities to potential places of interest (national parks, amusement parks, and just plain tourist attractions). There is also a city-to-city mileage chart in the front and a map showing driving times in the back. Most states also have a section to write notes as well, which is great for directions or the address of hotels or sites.
One thing that proved frustrating to me while traveling was the fact that the maps, which are indeed very large and thus quite detailed, often break a state (even a relatively small one) up into 4 or so pieces. This is great if you're focusing on just one corner of a state--bad if you're driving as much as we did at times. There were days when, had I used this atlas as reference, I'd have had to consult 6 or so pages just to get an idea of the route I'd be driving for the day. And don't try looking at a map of the entire US--that, too, is broken up into regions. Again, good for those seeking a lot of detail, bad for long distance travelers. I took another atlas along with me for this purpose. The spiral binding also proved annoying at times--if you want to find something that happens to land on the edge of the page by the binding, you'll find that part of the map difficult to read.
Overall, however, this atlas proved to be a very valuable reference, and I'm glad I took it even though space was limited in our car. As I said, however, if you're planning on driving a very long distance you might consider taking another atlas or set of maps as well, when you need to get a broader picture.