Utopia resort was perfect for our needs: it is quite, but in a perfect location respect to Lamai centre, close to shops and restaurants, it has nice beach services, sunbeds are free for guests, and the restaurant and bar is on the beach as well. The rooms are good, very clean, AC working perfectly, and they are towards the beach and far from the noisy street.
In addition, they have a travel agency very organised to plan last minutes tours, boat trips, snorkelling trips etc. On the opposite side of the street there is a scooter shop if you need to hire one.
Highly recommended.