You are quite right in the fact that Manala Hotel is new. Here is the only link I have for the hotel:
Personally, I don't know anyone who has stayed there, but every time I drive past the hotel, it looks very appealing and I think I would not hesitate to rent a room there if I was traveling through and needed a place to stay.
There are restaurants close by and the hotel is about a 5 minute walk from the beach.
I would not say that it is secluded in that there are other hotels surrounding Manala, but they seem to have created as private a place as possible with plants and trees.
Although the nearest beach location is popular to surfers, there are many parts of the day when the surf is minimal and you can enjoy the ocean without fear of getting pounded by waves or run over by surfers!
this link may also be helpful for locations of restaurants around Manala Hotel: