Culture separates Lyft from the rest. The pink mustache to me serves two functions: 1) it represents that culture that runs very deep and 2) it helps you ID a Lyft car in a fun, non-threatening way.
I use Lyft quite a bit, all of the drivers are great, friendly and people I don't mind spending 5-15 minutes with. It feels like getting into a car with a friend and is completely safe.