While I did wear uniforms (blue cardigan with white polo shirt and navy blue khaki pants) in a Catholic school for Jr. High, I really didn't care about it that much. The main reason is much like what TrikTopz said: no need to worry about what you got to wear the next day, which was really a load off my mind.
But it did have one disadvantage: limiting the amount of "regular" clothes I had in possession. So now that I'm heading to a public High School, I really have to start buying new clothes. It looks like I'll actually miss wearing a uniform!