First, let me start by saying that we (there were 10 of us total -- including 5 kids between the ages of 3-5) had a wonderful time at this house! We stayed at the house for two weeks and, to give context for our stay, we have traveled extensively through Costa Rica, Panama, and Mexico, and some of us speak Spanish. The set-up is ideal for two families traveling together (which we were) -- one family stayed upstairs and the other stayed downstairs allowing for privacy and comfort for everyone. The positioning of the house on the beach with the pool was very child-friendly and an overall delight. Further, the staff was simply incredible...really truly incredible!
That said, I wanted to comment on a few "issues" we had with our stay so that it may help others in their decision about where to stay. The single biggest problem that we encountered was the location. While it was conveyed to us that Granada was about 1 hour away and Leon was about 1.25 hours away, it was more like 2 and 2.5 hours respectively. Even basic groceries were about 1/2 hour away (there's literally nothing "local"). Since much of the other attractions in the country are in the surrounding areas around those cities (Las Isletas, Mombacho, etc), the distance was a HUGE problem (anyone traveling with children knows that 4-5 hours of round-trip travel time is quite different from 2 hours). I wouldn't recommend using this house as a base and/or for an extended stay -- just a beach house to go to and strand yourself at for a couple of days. Another issue (also relevant for families) is that, at least while we were there, the ocean was far too rough for kids (and most of the adults).
Other than those two major issues, there were a few other glitches. Some of those glitches may have to do with Nicaragua more than the house itslef...
We lost power three times in the two weeks that we were there (each for a very short duration) and we had no reliable internet for a full week (a major problem since that also meant no reliable phone) -- perhaps par for the course in Nicaragua....
Also, when it rained, a deluge of water would penetrate the house and flood the interior bedroom floors (so no toys and such could be on the floor).
Finally, we were contstantly needing to "supply" the house: Cooking gas, toilet paper, dish soap, etc --NOTHING was included -- not exactly what one looks for in a "relaxing vacation."
With the above said, if you know what you're getting in to, you can have a fun time!