It certainly depends on the city or the suburb but in general I would say that the city is my choice.
There are to general conditions that decide it; the option to be anonymous and the possibility to have local coherence.
My experience is that despite the distance between houses in countryside or in a suburb, people tend to get into your life in a way that might threaten your integrity. Somehow people who live in the cities tend to be better in letting you live your own life. On the other hand, if you live in large apartment blocks in the suburb the anonymousity can be almost devastating.
Furthermore I think that people who haven’t lived in the city underestimate the degree of social connections in the local community of cities. This especially applies to people with children or dogs. The network for these people are often very tight but, as I believe, with a better degree of integrity, you are not obliged to have contact with everyone as some latent community rule, just the person you like to mend with.
In any setup City or Suburb people who like to have social contact will try to have it. It may be a possibility or a problem to relate to them, but suburb communities where either everyone are totally blank or walks in and out of your life, changing husbands or wives, creating myriads of opportunities, just because the social expectation is that you take part in the local community are worse than a life in the city.
The City also tend to have places to go to instead of spending time in your garden or just longing somewhere else when you live in some uninspirational suburb blocks.
I go for the City!