The first thing that comes to my mind when thinking on Arenas del Mar is great service, eventough they have all other features covered (facilities, location, food) they truly go an extra mile to make sure your stay with them is pleasant (e.g. we were a bit late for our flight back to San Jose and as soon as the girls in the lobby noticed this, they prepared a whole, yummy breakfast to take with us on the way to the airport -fruit, juice, coffee and recently baked bread).
Being located right in the middle of Manuel Antonio Park, you will have access to one almost private beach (Playitas) and to Playa Espadilla Norte as well as to the exhuberant rainforest and nature just getting out of your room. To make the experience better, hotel's food is great, healthy and tasty!. The other most shocking fact about this hotel is their real committment to sustainability and to people. I guess the reason why guests feel so welcomed is because staff is truly happy working there. The team is like a family and it is refreshing and inspiring to see how they are treated (we were lucky enough to share the 5th anniversary toast and celebration with the staff)... Están haciendo un excelente trabajo equipo de Arenas del Mar, les agradecemos el servicio y atenciones recibidas durante nuestra estadía (Alfonso y Rosa, de Mexico)

One of the most beatifull hotels arround the all cental pacific if you want to enjoy of most famous and amazing flora y fauna of the area comming together with the most high quality level of personal service that you can get!!! ..they have also the most delicious meals you can think about everything was just great!!! The staff just became a great friends with me, they are just an unforgettable people that make you spend an unforgettable experience during all your stay there!! And if you also enjoy surfing this is a great place to do it, really good waves all the time and also many other great beaches nearby to surf that you can visit just to try othes really nice waves arround the area!!! So much thanks to all of them for giving me one of the most memorable times i ever had!!

Full disclousure: I've met the primary owner two times at cocktail parties over the past 12 years. We went there at his suggestion. I have no financial interest in this and this is our (my wife and me) true opinion of this resort:

We had an absolutely wonderful time at Arenas Del Mar this week! We don't normally take a "beach vacation" and it was great to have such a relaxing, beautiful and hospitable place to be, with no deadlines or stress.

Your staff deserve high praise. They were lovely, competent and dedicated, and struck the perfect balance between being attentive and respecting our privacy. One of our servers,Yahaira, was especially delightful, as was David. They really took care of us, as did Laura in the Spa. They said that they all feel the management treats them very well, and in turn it makes them want to do their best for the guests. We also had an absolutely wonderful young tour guide, Roger, who took us through the national park along with a Swiss couple; he was so knowledgeable and a great ambassador for the country. All of them worried that their English was not good enough, but we found them easy to understand and eager to converse. There were others who were also excellent, but I am unfortunately not remembering their names. Last but not least, David Calderone (driver from San Jose) was great! He gave us a nice "tour" across the country on our way back to the airport.

The room (really a suite) on the beach was one of the best I've ever been in. Especially fun was the daily show as the monkey tribe came through the trees right in front of us!

I have been asked by numerous friends and neighbors about the resort, and at least one family is going to investigate visiting over Christmas. The website is great and I've passed that link along to them.

Stayed at Arenas del Mar and loved it. Our room overlooked the ocean and it was huge! Loved the jacuzzi in the balcony and relaxing on the lounge chairs listening to the sound of the waves.
The Tico Bar (free minibar filled with Costa Rican specialties) was a really cool touch.
Had lunch on the private beach and it was great. Of course, had the ceviche.
Did the sustainability tour at the hotel (free) and it was really interesting to see all the things the hotel does to be green. It was fun to get a behind-the-scenes view.
The hotel is quite removed from the main road so you'll have to take a taxi if you want to go into town but that also adds to the experience!
Saw monkeys on the trees bythe pool: cappuchin and ti-ti plus lots of iguanas.
Overall a great place to stay!