I used to live in SoMa, and I still work in the Financial (though I rarely go in nowadays). The last few times I've been in the City, I have noticed it's simultaneously quieter on the streets downtown and also a bit more grungy. I do think the homeless situation is a little out of control, and those in San Francisco are a bit more aggressive than elsewhere, I've noticed. Still, if you walk with a purpose and don't engage, I'd say 95% of them time, they won't engage with you either.