It really depends what your requirements are. Is you focus on protection, looks, feel, weight, etc.
Personally I like the folio look, despise any covering of the ipad front (bezels?) and weight is not too important.
I have an ipad pro (12). If I could get hold of them, I would go for one of the pad&quill offerings. Apple make some excellent cases, especially the smart keyboard option, but IMHO the lack of colour choice, price and UK keyboard option is a killer.
My favourite case at the moment is the Stilgut leather Couverture, in brown. It meets all my needs.