I have not stayed at the Shangri-La Sentosa, but if you haven't already looked into it, try the Four Seasons. It's over in the Orchard area so it's not that central if you wanted to be near the Marina, but we LOVED our stay there. We were also traveling as a family of 4. They provided a rollaway at no extra charge. They also have a family pool on the roof and an adult lap pool on the main level. The "premier" room fits 4 people which is a corner room and not a suite. You can easily walk through the walkways to the Voco hotel and the nearby malls.

Also, if you are heading to Asia from the Americas or Europe, you may need to consider taking a day or two for the kids (and yourself) to adjust to the jet lag before going off on your adventures. It's no fun to run around with tired and sleepy kids.