Arenal Manoa is everything a resort should be. The staff is not only very well trained and polite, but they are competent and eager to help make your stay good, they also speak English very well.
The facilities were immaculate. I found not a single detail that had been overlooked, the room was large, comfortable, and modern with a nice, large and private patio with amazing views.
The breakfast buffet had something for everyone, plenty of fresh fruit, cereal, oatmeal, traditional Costa Rican dishes, sausage and eggs, and even an omelette station. The restaurant is a very nice place, although I found the selection just a bit limited and it might have made a difference if I was on an extended stay, but it was perfect for my needs. They make a great pizza, too, by the way.
The only thing close to a complaint I had is really not a complaint at all. The thermal pools are not very "thermal" They were about 30 degrees (86 F) and while warm, it was basically like a heated pool and not the sizzling hot jacuzzi like water I had expected. But the pools themselves are beautiful. There are several of them and they are typically about 10' in diameter, perfect for an intimate afternoon. They also have the people from the pool come around to ask if you want drinks, which is a plus. I loved my stay here, and I think you will, too.