Been living under a rock for the past decade? ALL large miners have come from china since at least 2014. The only miners from there as the small ones from Sidehack and the BitAxes. BTW: Bitmain is just 1 of several Chinese company that makes miners. Have you never heard of the Whatsminers, Canaan's Avalons, or truly crappy ones from the likes of eBang?

As for reliability and repair policies - DYOFR. The are pages and pages about that here.