I don’t know if one can evaluate a tweeter alone, , in isolation from other drivers in a system. There are many fine examples, that can work well in the right system, such as Magneplanar ribbons, pleated ribbons (e.g. AMT), and one of my favorites—Western Electric 597 fieldcoil compression tweeters. The 597 is particularly good at disappearing—you hardly know it is working. I heard a fantastic version of the 597 made by G.I.P. Laboratories (this tweeter costs $60,000 a pair); it is in the running for best tweeter.
What speaker has the best tweeter?
I love the AMT tweeters in my speakers. They are definitely different from other tweeters I have heard. I enjoy their openness and air. But there are qualities of other tweeters that excel in other ways. Some v pricy speakers use beryllium or diamond or diamond coated beryllium. I see that the price of, Seas I think, diamond tweeter is like $6K a pair. Then ribbons offer used. Not to mention plasma, etc.