I fly TACA every month. Connecting in SAL beats ANY US connection on the return. ANY , especially MIA. The prices are lower than AA by about 40% and the planes are newer. If you are in coach ( I fly Clase Ejecutiva) they feed you on longer flights for free.

SAL isn't the most modern airport in CA (MGA probably is now they have done all the renovations) but it is clean, open, and when you arrive (each way to and from ) and can go right to the next flight vs. through INS, Customs, TSA you will use it again or more accurately not use MIA ever again.

Note you may want to check on your flight bought from TACA vs. United. I suspect it will cost less and you'd still get your miles I think. For example TACA in C is $2500 less than United in B.

Note it is TACA not Taca. TACA is an acronym.

Note also they have about a 95% on time record - this is not due to magical powers as much as they really overestimate time per flight then come in 1/2 an hour to an hour early.