The two biggest things of interest are:
1. Not all of them have the Japanese-language option disabled from the boot menu, and
2. Either no one in Korea could refrain from opening their systems and mucking around with, and losing, the innards, or Sega foisted some pretty shoddy gear on poor Samsung. All three are missing parts and/or screws.
I've started a new page detailing some of the findings on the wiki.