At the moment, ZF is the only factory offering a high quality bronzo available for purchase. However, Kuvarsit has posted a production sample they are currently working on but the actual release date is unknown though some have mentioned that it should be available later this month.
For the ZF version, there have been some QC issues reported but it is a solid build. Tbd on Kuvarsit.
There were previous low quality versions of the bronzo produced using ss and rose gold plating and a 23J movement.