I've looked up some old topics on this, but most of them has very few posters and opinions on them, which is strange since presumably most of us wear shirts and those of us who customize our shirts or have choices open to us will at some point make decisions on which kind to wear.
For me I'm planning to make a dozen or so shirts and am not sure which cuffs to use, though I've had both. Specifically I'm considering them for my barrel cuffs, I think I'd far prefer square cuffs for my French cuff shirts, but perhaps some might disagree on that also.
Would you say one style is more formal than the other? I feel like rounded is likely the most conservative and safest choice, but is square more formal? Is corner slightly more dandy? How do you think they affect the look? As the wearer we rarely get to see the effect ourselves unless looking at a mirror so perhaps it's so minor and difficult to notice detail nobody really cares?