The Tenderloin, in downtown San Francisco, is a dump, at least how I remember it. There's "character" if by character you mean skid row like you see in the movies. It's like in "Escape from New York", except without Kurt Russell.

I used to take the bus most days from Van Ness to Market Street, right through the center of the Tenderloin.

It ain't pretty.

You know, there's slums that we should keep because they are where people live, and they serve a purpose.

Then there are those slums that should be either torn down or cleaned up.

The Tenderloin is that kind of slum.

Others apparently disagree:

In San Francisco's Tenderloin, residents aren't fighting the usual gentrification battle over displacing low-income families. Instead, they are fighting for the neighborhood's gritty ambience.

Often described by tourist guides as San Francisco's worst neighborhood, the Tenderloin has for years been a gathering point for pimps, drug addicts and transvestites and transgender residents, some of whom work as prostitutes. Some residents say that's what gives the Tenderloin its personality and makes it a crucial piece of San Francisco's diverse cityscape. Cleanup efforts, these residents contend, threaten to destroy an atmosphere that welcomes people on the fringe of society, who otherwise could find no refuge. And it distracts from the issues the neighborhood really cares about, such as safety for sex workers and affordable housing.

I don't know if you can use "gritty" and "ambience" in the same sentence.

To me, it's not really about gentrification, and displacement of people. It's about the natural progression of neighborhoods, from one group or groups of people, to another.

Complete story: San Francisco Residents Fight To Stay Seedy in Low-Rent District - By Bobby White, The Wall Street Journal Online