Sorry to upset you CX Fans...but on this routing BA wins Hands down....Unless you want to endure awful timing schedules on CX from DXB...No First Class...No Caviar...Terrible Regional Seating...Third Rate Business Class Food...Average to Poor Cabin Service...3 Sectors versus 2 with BA... Possible RJ Coach Only for final USA Domestic Sector...US Immigration, Customs and re-check Bags Farce at US or Canada Gateway

At the moment one of the 2 DXB-LHR is designated to be operated by New First and around 40% of the other 777 is likely to be New First.

CX Regional Business IMHO is Very Poor and for 8 Hours DXB-HKG I would never even consider it.

The only downside flying 2 stop BA is IAD Immigration and Customs but if OP is a US Citizen even this is endurable.

Finally if Caviar is important to you, buy some at LHR the BA Crew will be delighted to open it for you.

And the final deal breaker OneWorld awards would require 230,000 Miles against 157,500 for All Partner AAwards J to DXB and F Returning with BA. Although possible OP could change from OW AAward to All-Partner and potentially still endure 8 Hours in CX Regional Business Class.