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.
mglik
All of my designs have made the tweeter sound like the best one.  It's ALL about the design and the crossover, using the right tweeter in a given design.

That said, there are dogs, but most soft dome tweeters and decent ceramic tweeters can be tamed into very good performers.  
Several speakers in Usher's line use their DMD tweeter. Usher puts DMD in the name of such speakers. And their TD-10 and -20 have DMD mid-range as well as tweeter.
The tweeters on the Yamaha NS5000 are excellent. The beauty of that speaker is that the midrange and massive woofer are also made from the same material as the tweeter. No one else does that. 
Seas T35 exotic are pretty good value for money.
It’s ALL about the design and the crossover, using the right tweeter in a given design.
Matching drivers, using their strengths and relying on crossover points to diminish the limitations in a process of matching them together to form a cohesive voicing of a speaker - that’s art!