@Tianruo J I'm actually in a similar situation—non-Christian, focusing on Christianity and Judaism in the Roman-Hellenistic period, accepted to both YDS MARc and HDS MTS. I'm leaning towards HDS right now due to the ease of interaction with other departments and schools, the greater academic community in Boston, and—though I really don't care for most modern politics in my academia—the diversity at HDS. Yale just felt so WASPy, the div school was a little far from the rest of Yale, and the cost of rent was too high in the area for acceptable housing. Plus New Haven (or the Yale part at least) feels a little like an artificial town. It was so weird to not see any families or kids wandering around.
Plus, as you said, languages are important. HDS' summer language program (and how it is fully covered except for ~400 dollars) is a huge draw. Even though so many people at the HDS open house were asking questions about getting out of doing languages, it's a huge draw to me to be able to take intensive Hebrew or Syriac for relatively little.
But I'm not trying to convince you or anything, just working through my own choices in comparison to you.