Just returned from a 13 sector Business Class OWA that used six airlines: UL, BA, QR, RJ, AY and QF.
To my greatest surprise, the stand-out best flight was QF70 DEL-MEL. The seat was the most spacious for bed mode, allowing me to sleep in the recovery position rather than forcing me into an approximation of a straight line. This was also the only flight to use a mattress topper or to give me PJs. The design of the seat cubicle was well thought out with convenient shelves and racks to put bits and bobs in. The catering ex DEL was stellar with some genuinely spicy, tasty Indian options. The cabin crew were fantastic, attentive and chatty when pax were up for it. The crew were responsive to pax preferences rather than just running to a set timetable/formula. They fixed beds, helped pax with luggage and applied rules sensibly. Some pax were disappointed, though, that there was no champagne.
Runner up was BA - where I did pay extra to select one of the few sardine can seats that had both a window and aisle access on my DEL-LHR flight. This seat was so comfortable - which most of the J seats on other airlines were not. The catering, too, ex DEL was fantastic. I also flew BA on the Embraer 190 LCY-MXP and although the seats were the same as economy, they had plenty of legroom and were actually comfortable to sit on.
The only other memorable feature was RJ's use of a trolley service for meals, serving straight out of large containers onto plates - and a gorgeous embroidered uniform for some female flight attendants.
The other airlines - UL, QR and AY - were forgettable at best and pretty uncomfortable at worst. UL redeemed itself a bit with some OK food out of CMB, but their offering ex-Australia was dismal.
In terms of airports, HEL was the clear winner - beautiful, spacious and a super-efficient security process that minimised queuing.
My journey did teach me that it takes more than a 'door' to make a good business class seat.
Hope some of these thoughts help others in planning their journeys. It is worth the effort.