I didn't have a uniform in primary, and never felt the lack of it. I was the odd kid in secondary with the homemade skirt and coat and the 'wrong' pe kit but it never really bothered me - they'd have picked on me (short, ginger, fat, bespectacled and reasonably clever - I never had a cat in hell's chance!) regardless of what I was wearing. I remember my eldest sister having a huge stress about getting the right, suitably cool in the non-temperature sense, shorts for athletics and being completely perplexed because I couldn't understand why it mattered. I was very very fortunate in that I passed the qualifying test and interview (seriously - we had an exam on categorising and alphabetising and an interview with two teachers!) to be a volunteer school librarian. Which meant I won a magic badge (colour coded for what year you were in as I recall) and could spend every break and every lunchtime in there, and didn't have to queue for dinners, thus avoiding 99% of all bullying and misery until the blessed relief of sixth form. In sixth form there wasn't a uniformbut there was a 'dress code' of, iirc, 'suitable business attire in black, blue or grey'. I too challenged this in a few ways. Grandad shirts, fringed skirts, carrot-orange henna hair and a half shaved head didn't cause an issue. Wearing a headsquare did - they claimed to object to it being green, but then objected to a black one. And a friend got into trouble for combining patent doc martens with a mini skirt.... It was simpler when the rules were clearer further down the school. But less fun
The cubs' school, currently, has a voluntary uniform and I'd say roughly 2/3 of kids wear something approximating to uniform most of the time. This is likely to change and become less voluntary soon, I believe. School colours are navy and red. Official badged kit - polos, t-shirts, jumpers and cardies - can be bought from the school office, but tesco/asda/M&S/whatever equivalents are fine.
From a parenting point of view - it's easy. It's routine - and my boys respond well to routine. It clearly distinguishes school days - when we have to get out the door NOW from weekends, when we can pootle around and stuff. It's cheap as chips and we have hand me downs from other families that have gone through 4 kids before ending up on SmallestCub - we have one of the original run of t-shirts from the very first newly introduced optional uniform! It's all stuff that washes well. The odd bits that I do buy rather than acquire, I aim for comfy versions - as I would with their civvies. We don't have to think about it or argue about it. They don't change out of uniform when they get home - but then 3 days a week out evening routine is home/tea/bath/bed and try to get that all done in an hour and a half to avoid a late night!
EldestCub, btw, says he 'doesn't mind' uniform. He thinks it is a good thing when you're on a school trip as it helps to identify you. He couldn't think of a good reason to not have it. But then he consistently wears uniform on dressy-up days (he'll wear civvies on mufti days if we remember, but Doesn't Do fancy dress) and his favourite role in any performance is narrator - so he can just wear school clothes and doesn't need a costume....