Santa Ana holds the distinction of being listed by the Rockefeller Institute's top ten cities with the highest level of urban hardship, and earns it.
One the plus side, it has a lot of beautiful old architecture, museums, a burgeoning art community, some fantastic restaurants, and a vibrant latino (mostly Mexican) community. Fourth street in downtown is a veritable slice of Mexico, with specialty shops, street vendors and a general carnival-like atmosphere.
On the downside, it is mostly blighted, traffic clogged and poverty-stricken. Downtown is barely liveable, with not many practical businesses (groceries, dry cleaners, etc.) for residents. The outlying suburbs range from bland to life-threatingly terrifying.
Live somewhere else, and drive in to see the good parts.