What speaker has the best high frequencies?

I have a Spatial Audio X5 with a wide band horn loaded AMT (Air Motion Transformer) which handles high frequencies (1k and up?). It is big, about 6” x 1”. I feel it is much better than the 1” tweeter found in most speakers.  I honestly don’t know how this AMT is different from, say, ribbon tweeter.  This leads me to think, who or what speaker has the best high frequencies?  I heard good things about the B&W diamond tweeter, but it is still a 1” tweeter.  What else is out there?  I think size makes a difference.  In this case, is it a larger ribbing tweeter better than most 1” tweeters?