I tested using Sanity with Next.js in a small POC and had an overall really great experience.
It was easy to work with the schema system to create the data structure, and it worked fine for what we need with the Storefront.
The new live preview system was a bit buggy. It worked most of the time but sometimes didn't sync the data properly between the editor UI to the website preview. This will get better over time.
I liked the interface / UI that is presented to the editors to create content. It is very easy to use and it has everything we need.
The media library and file storage seemed to work just fine.
The pricing seemed very reasonable with 15 dollars per seat per month.
There are 2 datasets (databases) available that I think will work fine for what we want to do.
Deployments are super easy for both the source code and for updating the database from the UI.
Creating static menus with Sanity worked just fine. I had a bit more trouble when the menus had to be dynamic based on the document structure. More research has to be done on this, it seems possible.
Sanity has all the field types that one would need. Texboxes, images, checkboxes and so on.
I want to test Sanity to make an estimation on how much work it would take to implement it on the Storefront.