To clarify, I have tried a pair in both sizes, but I can't try to cycle in them.
The size down is quite snug, the size up is more comfortable. It's also a bit of an odd fit, because the sole is even more rigid than, say, the Vans sole. Weirdly, both sizes slip a bit on the heel 🤷🏻♂️ If I were to use them only as casual shoes (without cycling), I would size up, but when I cycle I usually like a snug fit (on my SIDI, for example), especially on fixed. Hence the hard choice.
To clarify, I have tried a pair in both sizes, but I can't try to cycle in them.
The size down is quite snug, the size up is more comfortable. It's also a bit of an odd fit, because the sole is even more rigid than, say, the Vans sole. Weirdly, both sizes slip a bit on the heel 🤷🏻♂️ If I were to use them only as casual shoes (without cycling), I would size up, but when I cycle I usually like a snug fit (on my SIDI, for example), especially on fixed. Hence the hard choice.