It's got to do with the jamma connector. The HRS (Hirose) is made in Japan and used on alot of original candy cabs. It is reasonable good quality but can crack at the ends making it possible to misalign the pins and cause damage. This can be avoided (mitigated may be a better word) by ensuring pin 7 is keyed.
The Taiwan future is the light blue Chinese (maybe taiwanese) made jamma connector (I think as i think the black one is chinese made). This connector is a little cheaper than the HRS but I actually prefer it as it doesn't seem to have the issues of the hirose. I do tend to key it anyway and if you don't have access to a 3d printer to print a bunch.of keys DM me and I'll post you some.
