AA has a decent operation at ONT now with the merged operations from US and AA.
It is true that there a number of insider secrets about ONT travel including availability of awards, etc.
AA uses three gates for active flights and up to three other gates for overnight plane parking. SNA is still preferred over ONT for various reasons including an Admirals Club and ORD service, but because ONT has no curfew, a late night DFW flight is scheduled at certain parts of the year.
The closest parking is the $18 lot across from T4, but the $9 lot is not difficult to reach by shuttle or longer walk.
I wish ONT got an ORD or a PHL or CLT flight at least a few days a week to really remove the need to go to LAX.
Rasheed