Currently wearing Sidi size 42 and they fit well.
I have low volume, slightly narrow feet, which only a few bike shoe brands work well.
Google isn’t helping much. Some say Vittoria’s are high volume, some say they fit like Sidi.
Anyone?
For what it’s worth I had a par of Vittoria’s and found them pretty uncomfortable. I have a high-volume wide foot and I could not get comfortable in them, So maybe they’re fit you foot style better. Another thing I struggled with is I felt like the cleat placement was really for forward. I had the cleat as far back as I could and still felt it was a touch too far forward.
Vittorias are wider. I’ve US 10 size foot and I wear size 45 Sidis and size 44.5 Vittorias.
Can’t use 44.5 Sidis as they are too narrow for me.