I have stayed at both Sipadan Water Village (SWV) and SMART Water Bungalows. As the old saying goes, you get what you pay for...the accommodations and food at SWV are good but not great. When I stayed there, the food was generally under seasoned and quantities at the buffet sometimes ran out. The under seasoning may have been an attempt to appeal to everyone and offend no one. However, no excuse for underfeeding guests. But the price is good value.
At SMART, the good is 5-star restaurant quality and there is plenty of it. In fact, I would go so far as to say that it is the best dive resort food I have ever had and compares very very favorably with just about any restaurant buffet I have had anywhere (let alone at a remote dive resort location). In fact, the food, though buffet style, tasted like it is cooked to order. Me and my diving buddy were constantly amazed at the quality of the food during our stay (and he is a "foodie"). Nothing dish is repeated during the week.
All meals consist of a selection of 4-5 hot meat/seafood entres, along with bread, fruit, and dessert stations. Breakfast of course has the cooked to order egg/omelette station, along with the afore mentioned standard food stations. Lunch and dinner consist of the 4-5 meat/seafood selections...things like chicken cordon blue, chinese style mayonnaise prawns, lamb curry, sauted steak, whole crabs, lobster thermador (yes, no kidding), au gratin potatoes, chinese styole ginger beef or oyster sauce beef, the list goes on and on.
In fact, SMART would be a great place to vacation even if one wasn't a diver...there is a decent beach on Mabul, pool, small spa, nice reading luange, and 3 gourmet meals a day.
However, you do pay for all this great food and luxury. Also, be sure you book SMART Water Bungalows and not the SMART chalets (which are on Mabul Island proper and not over the water). The chalets are nice but basic and they, of course, do not get anywhere near the food quality/selection that is served to Bungalow guests (believe me, one nite for fun, we checked...if they could see what the bungalow guests received we joked that they might storm the dinning hall).