I recently guided some clients who used the Mapache Rental Car Agency. We had one issue but I think it was handled as well as they could. As we reached our spot for lunch after a morning of birding in Carara, we noticed that the temperature of the engine was in the red zone. We hoped it had something to do with overusing the air conditioning so we enjoyed our meals and watched vultures, Wood Storks, caracaras, and a Bare-throated Tiger Heron scavenging fish waste on the beach (fishermen were unloading dozens of large pinkish Conger Eels along with a few big Red Snappers).
Upon checking the water, it was empty so we filled it up and left with high hopes. Unfortunately, the engine went right back up to red just as we reached the entrance to Bijagual and Villa Lapas. We pulled off the highway into that road, parked the car under a bit of shade and called Mapache. I explained the problem to them and they said that a mechanic was on his way. That was fine but he was coming from San Jose so could take 2 hours to get there! This was an issue because we were essentially stranded, clients were elderly, and it was pretty hot. There was nowhere to buy water and my car was back at Cerro Lodge (too far to walk). I called Cerro Lodge and they came through by sending an informal taxi. He took me to my car, I bought water, and headed back to clients and the stranded vehicle.
Clients decided to call Mapache and see if they can leave the car while I drive them up to Alajuela (they were leaving the next day). Mapache was insistent about them not leaving the car there unattended and just kept saying that the mechanic would come soon despite clients saying that they were stranded. When asked about the possibility of not being able to fix the car, Mapache just insisted that the mechanic would fix it.
As 4 pm approached (we had been there since 2), we decided that we would give them until 4 before calling Mapache to let them know that we had left the car there. Luckily, the mechanic showed up just after making that decision, quickly realized that the car needed a new radiator and did the paperwork for clients to take the car he had driven.
Everything turned out fine and I think they did as a good a job as they could considering the locations of their offices. However, I think they should have let their clients know that the mechanic was bringing a car for them to use in case they needed it as they were pretty worried about being stuck there (although I would have driven them back in any case). In retrospect, we also should have just called them as soon as we got to the restaurant. That way, the mechanic would have probably arrived not long after lunch, and it would have been more comfortable than waiting on the road to Villa Lapas. At least a side benefit was seeing several new birds for the day including an Orange-fronted Parakeet that just perched directly above the car for most of our wait.
In conclusion, I would certainly recommend Mapache, always call the rental agency as soon as there is a problem with the car, and carry plenty of water in case you get stranded!