Safety is relative. What I consider safe might not be what you consider safe, but it works for me. I've lived in south philly, Fishtown, and center city over the past decade-plus and only once ever had an incident I thought warranted the cops (found out they can't do much for a purse-snatch, of course). Neighborhoods like the far northeast or Roxborough are actually pretty big and can be very different places from block to block.