Having owned MO with Arabic numerals and then seeing the MO with Roman numerals at Basel fair, my choice is the MO with Roman numerals anyday.
This was the same choice I made when deciding on the Ulysse Nardin 1846 Marine Chrono with Roman numerals. The numbers fit the dial better and historically are correct for a Marine watch.
i prefer the look of the MO-Romans. IMO, a little more sober and masculine.