I love these shoes so much. I rotate through 2 shoes and these are one of of them, the other shoe I use is the Angelo Luzio 4-way total stretch.
I wear a street size 38, and have egyptian style feet, I use a size 40.5C or 9C. I tried bigger and smaller sizes and size D as well, and these fit the best. The 8.5C was really just a size too small but gave me cramps as the length was too short. As my foot changes (Im an adult ballet beginner) my foot is getting a little wider, so I may try the 40.5D for more toe splay, but its a tinch baggy. The C is a great width as the stretch of the shoes is easy to stretch. For comparison, the Bloch infinity stretch and synchrony ballet shoes are thicker fabrics with a tight stretch, so if you have wider feet its really hard to get good toe splay unless you have really strong feet. I couldn't use them even though I liked them.
The fabric of the Nikolay is more of a stretch canvas as opposed to the finer weave of the Capezio Hanami, and it also looks nicer on my feet than the Hanami. It is single layered (the hanami seems to have a lining which also causes my feet to get more sweaty), and the metatarsal pad isn't so thick that it makes me unbalanced, but is still supportive. The only qualm I have is the color fading over time near the big toe on the side due to doing rond de jambes. So its a ballet pink shoe with some of the color rubbing off. Not a big deal as it has no effect on functionality, but something to note. I have been using these since December 2022. I feel really secure in these shoes and recommend them!!! Sizing can be tricky so order a few and return what doesn't work.