We stayed at Sonaisali too. It was a nice resort not far from the airport but as Kelly said, unless you go to an island you are not going to get a good beach, you have to get off the mainland for the good sand, diving etc. My DP was so bored in Fiji that he took a boat out at the resort and I swear he tried to sail his way to New Zealand just for a change of scenery! When we went we did not have kids and I would probably not go back again although all the kids at the resort were having a lovely time and the Fijians ADORE kids. My advice would be to pay extra and stay on an island off the mainland.