That's insane, one account with 20% of global hash rate.
Thats Halong Mining doing QC...they have not shipped yet
Got to love that QC control (secret version) probably call it 'pre-QC' they were likely doing the last 3 months

IMHO
I know for the BTC miners ..it is pretty much a wash...for what they paid in Nov 2017 for them, compared to just getting Bitmain units also shipping this month.
Then again BTC price was high, back in Nov 2017, WTF, so maybe it all will work out for them also...who knows?
at the BTC miner end...not so sure this SiaCoin Halong miner will last very long...I see it like the D3 from Bitmain...very first in line, you are probably OK on ROI...the rest
after 1st group..iffy as hell