If you only want to show a couple of LayerOverlays, you can use the StaticOverlay / DynamicOverlay. If you want to use other Overlays (like GoogleMapOverlay) or you want to use more than 2 LayerOverlays, you need to use the CustomOverlays.
StaticOverlay / DynamicOverlay is for the simple scenario, it simply divide your layers into 2 groups, one represents a static image which seldom changes like the map background, the other is relatively “dynamic” which has chances to be updated in the application, for example a small car running on the road. Here are the differences between the 2:
1, DynamicOverlay is always on top of the StaticOverlay.
2, StaticOverlay by default is a baseOverlay while DynamicOverlay is not. At one time, one map can only have one baseOverlay but can have multi UnBaseOverlays. In OverlaySwitcher, a baseOverlay is with a radioButton(so you can select only one) and an UnbaseOverlay is with a checkbox(so you can multi select).
3, StaticOverlay uses Tiling by default but DynamicOverlay doesn't
Hope that helps.