The only time I've ever had to wear a uniform was in primary school, and even then they weren't incredibly strict. In high school, we have a dress code, which I don't really mind. It actually makes it easier in the morning, because it means that I know exactly (or near-enough) what I have to wear.
My friend, who comes from France and where they have nothing like a uniform what so ever, has told me that he was never aware of any uniform-related bullying. So I'm kind of ambiguous about uniforms. They aren't necessarily bad, but nor are they necessarily good.