We were a very diverse family group of 12 - ages 11-70 - and Casa Britto was absolutely perfect for us.
First, location - the Central Valley is totally under-rated as a home base during your Costa Rica stay. The weather was always fresh, never hot, and the location is central to so many day trips within 1-3 hours - coffee plantations, national parks, volcanoes, zip lines, and the beach.
The house itself is incredible. So beautiful and well-finished, but at the same time as comfortable as home. Spacious but cozy. Beds so comfortable. There was easily enough space for 12 people to hang out together as a group or separate into smaller sections of the house with the privacy to enjoy quiet time and reading. There are many smaller sitting areas throughout the house and the outdoor areas to enjoy with sub-groups.
For our entire stay we lived a seamless indoor/outdoor life with the doors and windows flung open , as one is able to do in the moderate Central Valley climate.
We had one issue with the swimming pool heat (you do need heat because the nights are cool) but the owners promptly rectified the issue with a repairman, even though he was called the day after Christmas.
The only minor nuisance is that the next door neighbor seems to have about ten dogs that sometimes act as alarm clocks at the crack of dawn, but that is to be expected to some degree throughout the country, and after a couple of nights it was less noticeable - and the barking was for minutes, not hours.
We would highly recommend hiring the cook, Jasmine, who prepared a dinner for us one night - absolutely delicious food and a joy to be with her. And a very reasonable price.
The housekeeper Cristina was also very helpful with connecting us to local services - we needed a doctor/pharmacist for one of our family members.
From the beginning, the owners were very clear and helpful about the process of getting to the house from the airport and other details that needed to be worked out before and upon our arrival.
Usually on the last day of a vacation, you move to the "it'll be nice to get back home" phase. But here, we really didn't want to leave. Highly recommended.