For me, this is the biggest difference. When I live in a city, I know my neighbors just because. Running into each other on the bus turns into a beer and a long chat.
In Suburbia, you know a lot of your neighbors, but there's almost always some sort of reason or structure. The social network is the same size, but lots of those relationships are somehow not intrinsic (which isn't to devalue them, even comparatively, but imho there is a qualitative difference).
The latter works great for family life because there are so many more structural incentives to interact; the former is probably preferable for younger or non-child-raising people.
In Suburbia, you know a lot of your neighbors, but there's almost always some sort of reason or structure. The social network is the same size, but lots of those relationships are somehow not intrinsic (which isn't to devalue them, even comparatively, but imho there is a qualitative difference).
The latter works great for family life because there are so many more structural incentives to interact; the former is probably preferable for younger or non-child-raising people.