Does anyone have opinions on the merits of The Crew vs American Truck Simulator?
My answer to this, regarding ATS, would be "How much do you enjoy 'head empty' gaming?" Does the idea of a game where you have to plan ahead and use retarders/engine brakes to slow down instead of the foot brakes*, or navigate narrow streets and depots in a big truck, interest you? If the answer is "yes" then you'll get a kick out of A/ETS.
To tell the truth, I've never played ATS, but I've put many, many hours into ETS. So as far as cities go, if it's anything like ETS the answer is "it depends." In the decade-and-change that ETS has been around, the game has changed significantly in art direction and implementation. As a result the quality of the cities depends on whether you are in an older DLC area/base game area, or a newer DLC area.
In the early days of ETS, cities adhered to the 20:1 scale that the rest of the map does. This meant that there wasn't really enough room to capture the personality of each individual city. Basically every city was like 4 blocks of depots and maybe a gas station. Imagine that one really unflattering shot of Breezewood, PA. That's what every city in early DLCs looks like:
In the later DLCs, they detached the cities from the scale size, so if you blew them up to 1:1 size, they would be two-to-three times larger than IRL. This allowed them to give the cities much more character. You can't go down every street, but the city maps are elaborate enough that you get the idea. Here's a video of someone driving through Italy:
Italy was the first DLC that implemented this new style of city. Obviously all this applies to ETS, but since ATS is developed in parallel, it's not that wild to assume the same thing applies. FWIW the base game includes California, Nevada and Arizona. So I would guess that at least these states could be considered "early style."
One final note is that SCS, alongside developing new DLCs, is currently working on updating the older areas of the map to bring them up to the standard of the new ones. As of writing this, the California rework is ongoing.
* The need to use alternate braking systems depends on whether that option is turned on in the simulation settings. They are used automatically by default, I believe.