literally just came back to hong kong from abaca and i can only recommend it!!! some of the best - if not the best - service we ever experienced at any resort in asia. we told them in advance that we have a baby with us and they pre-arranged everything for him (toys in the room, baby bathtub, sterilizer, baby bottles, cleaning equipment, cot in the room and a cot on the boat when we did a boating trip, etc.). they also have nanny quarters for a much lower price, so we happily took our helper with us.
the only downside is that they do not have much of a beach as such. in the resort, you would mostly hang out in the cabanas around the pool.
incidentally we had a dinner at the shangri-la beachside. not a huge beach either (cannot compare with hainan for example) but at least some sand. the shangri-la grounds are also pretty huge, so if you like walking around with your buggy, shangri-la might be better.
on a separate note, the food at abaca is amazing too. shangri-la and hilton do not even come close to that quality.