Hi Barbara,
Liberia is recently expanded and very nice. The roads are fine and it’s actually the airport of choice to many of the largest resorts in the country and most popular expat centers. Much less crowded than the San Jose airport.
But Liberia, in the far northwest of the country, is about 5 hours away from San Jose. So which airport you fly into really depends on where you plan to visit in Costa Rica.
If you’re headed to the northern Pacific coast (towns like Playas del Coco, Tamarindo, or Flamingo) definitely fly into Liberia. If you’re going to the Nicoya Peninsula (towns like Samara, Nosara, Montezume, Malpais), Liberia is also best.
Arenal is about halfway between Liberia and San Jose – so if you’re going there it’s a toss up.
But if you’re headed to the Central Valley, Central Pacific coast, South Pacific coast, or Caribbean, San Jose is the better option.