Which Tweeter preferred- dome natural material, Beryllium/Metal or Planar Ribbon? Why?

Arguably two of the best German speaker manufacturers, FinkTeam and Wolf von Langa, employ custom Mundorf AMT tweeters, and they sound fantastic.

I truly believe there’s no such thing as the best tweeter, especially if you limit to material only.

The best tweeter is the one that perfectly integrated to a given speaker and the other drivers. I’ve heard ribbon tweeters that sounded odd (poorly integrated), Sol tweeters that sounded lifeless and metal dome (and inverted dome) that was like ice picks. On the same token, I’ve also heard the complete opposite of all… it comes down to the designer and how that fits your preference. 

As has been said, any tweeter is only a good as the overall speaker design. The Focal Inverted Ti is a good case in point - a unit that can sound radically different in different applications.

However, purely to expand the field, plasma tweeters e.g. the Lansche unit do have some pretty special qualities.

In mho....I have a pair of the full dipole ESS AMTs that sail away from anything else I've heard in terms of  what you can subject them to....

Get the xover right and pair them to whatever can 'keep up with them' in a space prep'd for dipoles.

Effortless.  And if you overdrive them, the element is replaceable...

(Always thought a line array of them would be scary....)

...but I'm just weird....*L*

There are too many good and bad implementations of each of these materials.  I have heard incredible Beryllium tweeters and painfully bright ones.  I have heard awful diamond tweeters, I have heard brilliant.  Same with ribbons, ceramic, aluminum, AMTs, etc.  There is not best material.  The total system drives the greatness or mediocrity of a speaker.