The highest quality i have seen is 9260 and i want to know if there is a higher quality steel.
Types of steel are one issue. But the quality of steel no matter what type is even more important. The only way to be sure that you are getting a good blade is to buy from someone that already has a reputation for producing great blades. Stop the questions about who thinks what type of steel is best and investigate the steel blades offered by companies like Bugei Trading company. they have good blades. Opinions vary, but Bugei has proven that they make good swords. That is all that is needed to be known. Any questions you have are best directed to them, not here.