[[Dr.Zed]] and [[TMTLogic]] are two different persons. We simply call both cards SYMBiFACE, since the first one was a [[SymbiosiS]] production.
The SF3 was, in a way, the successor to the SF2, as it's again multifunctional hardware, offering many components that are also particularly useful under [[SymbOS]]. However, they're not compatible and were built by two different hardware developers ([[Prodatron]] simply supported both projects and helped with shipping).
The RSF3 reunites the lineage as it is compatible with both the SYMBiFACE 3 '''and''' the SYMBiFACE II (and also with the M4 Board and many other CPC hardware expansions).