Being based in New York now and with JFK more convenient from home than EWR, I looked at the alternatives, but UA remains by far the best choice given my flying patterns: I fly around 100K per year, mostly for work, all must be booked in economy; international travel is typically to FRA or GVA, with an occasional trip to Asia.

DL makes little sense since, at my level of flying, I won't get any international upgrades.

AA does not work, either. On UA, I upgrade on a nonstop and sleep my way to FRA or GVA. Or, even better, I can now upgrade in advance on LH and they are finally converting their business class to flat-beds. On AA, I would only be able to upgrade to LHR (less time to sleep, and every hour matters on overnight transatlantic flights) and I'd to have to connect from LHR as opposed to flying nonstop - huge hassle all around.

Asia is even worse. With AA, I'd be flying in economy on CX or JL. On UA, I use my GPUs to upgrade to business, so UA is a clear winner.

Award availability is another one. With UA, I can usually find transatlantic award seats. It's not what it used to be, but still possible to find business-class awards through secondary cities like BRU. AA, in my experience, is a horror show - there is hardly any availability on AA itself, and all BA awards involve hundreds of dollars in junk fees. Plus everything seems to involve connecting in LHR as opposed to nonstops on UA and partners.

Smaller benefits matter, too. UA automatically gives my 1K status to my spouse, which is convenient when she travels on her own. I can use RPUs to upgrade 10-hour flights to Hawaii (I don't think AA even flies to Hawaii from NY). Economy Plus always seems available, etc.

And if not AA or DL, then what? Of course, I am not happy about the devaluations, but for me UA is still heads and shoulders above the alternatives.