From my local, and my most convenient, international airport of BHX I will select my flights based on sociable schedules, then price, then quality of cabin service and then if I get points that don't expire after a period of time.
In this respect, when BACX operated from BHX I never flew with them once, I would always prefer to fly with Swiss, then KLM, then SAS or Lufthansa and with Air France bringing up the rear.
If Swiss were to withdraw the quality of cabin service then they would drop down the list, if KLM were still declining to serve alcohol, paid for or not, in economy class then they wouldn't even appear on the list, SAS charge for food and drink but their cabin service is good and if Lufthansa drop their 'quality' of service any lower then they'll be following behind Air France!