Jaffa today has been completely surrounded by Tel Aviv, to the point where you can't tell where one city ends and the other begins. A decent number of the buildings from the British period are however still still standing there, so it is (in my opinion) substantially more charming than most of Tel Aviv which tends to be newer. It gives off a vibe of colonial holiday anno 1925, or at least that's how I imagine it.
37% of the population in Jaffa today are Arab, which is pretty high by Israeli standards and makes it a "mixed" city. When I was there I was told it was the Arab neighborhood, which however seems to be a bit of an exaggeration. But at least it has Arab neighborhoods.