it both is and isn't
OSSC is much better than the Taito Scan PCB but the Taito Scan PCB is much more simple/cleaner to install
Jammafier is arguably easier to hook up than the official JAMMA kit harness but the Jammafier solution means the buttons wires are encoded into JVS by the JVS IO and then the jammafier decodes the JVS back into normal wire signals, so it's a complicated and unnecessary process to hook the buttons up to your PCB. conversely The Taito JAMMA kit harness has 0 lag because it's just wires straight through from the buttons to the PCB.