Originally Posted by
synzero
As for me, I’m traveling most between west and east coast round trip, usually LAX to JFK but occasionally between LA and SF though I usually go Southwest for that given their no fee changes.
My main consideration is I need enough legroom in coach to work on my laptop (32” absolute minimum), WiFi needs to work, and food quality (either onboard or in the terminal to go) and IFE are also factors. Lounge access is also important; I’ve been doing Centurion in SFO then walking across to JetBlue, which to me is worth the 10 minute walk, but Delta SkyClub is appealing.
I think the biggest question I'd ask you is "how much will you fly in 2020?"
It sounds like your comparison is based on having no status with either airline.
If you fly enough to reach Mosaic with JetBlue, the benefits may be appealing -- no change fees on (non-basic) flights, and steeply discounted EMS seat purchases with points being the two that jump out at me.
At least for me, Mosaic offers more than Delta Gold Medallion, especially now that Comfort+ isn't at time of ticketing.
If you fly enough to hit $75k (and the requisite MQD), I suspect the Delta Platinum experience would edge out Mosaic.