IME, as a frequent flyer of both airlines--the weaknesses in both exist but there are some stark differences.

AA's weaknesses are operational efficiency, hard product, baggage, & route network. On the ground customer service is usually stellar.

UACO's weaknesses are a bit different. Soft product (particularly PMUA), customer service on the ground (polar opposite of AA), and the so-called elite desks.

UACO's business model appears to be single flight profitability over loyalty in almost every case. Status is the *last* thing that matters. We'll see what happens next year.