Practical pros & cons of concentric drivers (Tannoy, KEF etc)

[greatwhite]

I've always been a fan of concentric tweeter/bass driver concept as employed by the likes Tannoy and KEF (and now Fyne Audio) from a point of view of the full frequency range emanating from one spot. As I've read on various sites that there are a number of technical challenges that go with building such drivers which might by why so few manufacturers bother with them, but I was hoping for some insight from people that have had these type of speakers on the typical strength and weaknesses in day to day use e.g.
Are there consistent areas where these unit have difficulty? Sonically, setup, mechanical...
How does their reliability compare to conventional separate driver speakers?
If they do fail, my understanding is they are more difficult to fix. Any experience in this regard? Typical pitfalls if any?
Apart from the 'single' sound source are there other advantages people have found?

Thanks in advance

 

[Nchebe]

 

[Timber_MG]

 

[Katji]

 

[Agaton Sax]

 

[Katji]

 

[Juventino]

 

[Agaton Sax]

 

[jlaubza]