We had an amazing stay at Marianna's place. First, the view from the balcony is stunning, even better than what you see on photos! The apartment is spacious (we were two adults with two young children), clean, and very well equipped (we were even welcome with fresh oranges from the garden and delicious lemon pastries!). It is also very well located: it takes about one minute, by car, to reach the village, supermarket, restaurants, cafes, and the beach. You could also walk but we didn't choose this option since they are plenty of free parking in the village. Since the apartment is not directly in the village, it is super quiet, day and night.
Marianna (as well as her partner and her father) was very kind and helpful. It was also very easy to communicate with her for the whole process (for booking and during the stay as well).
We just fell in love with Santa Maria Navarres. It is a peaceful and small village with awesome beaches close by. Lonely planet qualifies it as "unpretentious" and it is exactly the feeling we had. It is also greatly located to discover many of Sardinia's gems. We spent 10 days there: we would have loved to stay for the whole summer!!!