We visited Costa Rica in mid July 2012 (mentioned July 2013, but Trip Advisor didn't give me a choice earlier than October 2012) on an REI family adventure trip. Hotel Mariposa was one of the three hotels we stayed, the other two being, the Arenal Observatory hotel near the Volcano and Hotel Bougainvillea in San Jose. The other two were also quite nice.
Hotel Mariposa was a beautiful hotel with an infinity pool with changing colors at night. Only complaint is the the hot tub wasn't all that warm. On the open restaurant terrace during breakfast, one could watch the birds soar by, sing their trill songs, view the beautiful ocean and coastal shores as well as watch the sunset in the evening.
The rooms were extremely spacious. There was TV in every room.. There was a bit of a walk for some of the rooms, which was my only complaint and that because of the humidity, a lot of bugs were able to escape into the rooms.
But the location couldn't have been better. It was a very short walk down to the main town with loads of wonderful restaurants and shops.. and a very short taxi or bus ride down to the Manuel San Antonia National Park with an abundance of protected wildlife, from sloths, to spider monkeys, orb spiders, raccoons, iguanas, white faced capuchin monkeys and if you were lucky to see them, crocodiles! And I need to mention the wonderful hiking trails and beautiful beaches.
Mid July was rainy season for Costa Rica, but were were lucky to have been rained on only one afternoon throughout our 10 day trip.