Daphne That's a pretty big assumption yes, one that's wrong. I'm not here for confirmation or anything. That being said, i don't mind giving some of that info if it helps.
OK, since you asked what we think, I decided to take you up on it. My idea was based on that you selected thighbands, and the shortest possible chain too, after asking about it here. But since my assumption is wrong, I was thinking that we might be able to help you if you give us a list of pro's and con's for you for both options: that would give us an idea what is important to you in the choice, and we can perhaps tell you what we think of them, and come up with more.
Lea you exactly know what to wear
Yes, that is of course the standard advantage of uniforms: no need to choose, and apart from that more equality between rich and poor kids (visually).
In what way is the cold weather relevant? Do you find it harder to pick, and match, a winter outfit than a summer outfit (if not in uniform)?