Hi Graham
That ticking away must be like music in your ears... 
I believe the fastest I have is 28800 A/h or 4Hz on several watches.
But would actually love a Zenith El Primero calibre.
Plus
must be precision and on a chronograph the resolution.
minus
must be more wear and maybe less 'reserve de marche'
Best regards
Hans
P.S. would be interesting with a post on the topic..maybe from Ginger..