It's great. I've lived here eight years.
All walks of life. Old, young, black, white, gay, straight, immigrant, native, wealthy, not-so-wealthy. You name it! The only people we have a shortage of are stuck-up people (nobody stuck up will feel very good here:)).
Crime seems low. I don't really know the statistics, but sometimes you hear about a gang-related offense. There is lots of graffiti, but seems to be under control to some extent, especially as the Mission / Geneva intersection / corridor or whatever it's called is going through some sort of revitalization.
Overall it's a good buy because lots of "homeowners" who couldn't really afford it are being flushed out, and making room for people who aren't looking for the next house to flip - which was rampant since even before I moved here.
It has a long ways to go to be, in my opinion, NICE. But I think it's been headed in that direction.
Oh, I wouldn't buy here if you have kids (don't think the gang problem is under control, enough). It's just my opinion, though. At least not until the schools improve a bit more, or unless you plan to send them to a private school. I think it's best for single people or a couple who is just getting started.
It's very central. So you can get to the peninsula or anywhere in the city pretty easily. Public transit is great because we have two BART stations on either end, as well as MUNI.