I stayed at the Harmony with my friend in June 2012 for a week. It is my personal favorite of all time. It is small yet luxurious and super eco-friendly. Decor I would describe as modern with a retro twist. The staff are very friendly and attentive, know you by face and name. Food is excellent. All meals were terrific, with my favorites being the smoothies, margaritas, and sushi. We spent most of our time surfing with Safari Surf school which is located right next to the hotel (and is really great!), or by the pool. We did a lot of poolside eating and napping- service poolside was great. There were a good amount of people staying there but it was never loud or hectic. My favorite part of the rooms was the private patio with an outdoor rain shower-um hello I want one. The mint shampoo in the rooms was pretty awesome too. AC worked great.
Location is wonderful. It is right next to the beach- like most hotels in CR it is set back from the beach for environmental preservation reasons but there is a path from the hotel to the beach and is about as close as you can get. Grounds are lush, tropical, and very well maintained. Playa Guiones is a spectacular white sand beach with a great consistent surf break. Didn't get to the yoga classes although we were offered 2 free classes when we checked in- next time!
Sadly when my friend and I tried to book our return trip in October for this upcoming Jan the Harmony was already full- sigh, looks like everyone knows how awesome it is. So make your reservations well in advance!