The cabanas by the Menehune Bridge are #'s 1 & 2. The Ka Maka landing cabanas are #'s 3-5. We definitely preferred the MB cabanas due to the location (central to everything). It may be a little noisy, but that didn't bother me at all. DD loved playing at the MB, so it worked out well.
They let guests pick their cabana location based on when they book, so the earlier you book, the better chance you have to choose your location.